Lamarck, the Founder of Evolution - His Life and Work
by Alpheus Spring Packard
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"In regard to these two modes of execution, if observation taught us nothing we could not form any opinion which would be well grounded. But it is not so; we distinctly see that there exists an order of things truly created (veritablement cree), as unchangeable as its author allows, acting on matter alone, and which possesses the power of producing all visible beings, of executing all the changes, all the modifications, even the extinctions, so also the renewals or recreations that we observe among them. It is to this order of things that we have given the name of nature. The Supreme Author of all that exists is, then, the immediate creator of matter as also of nature, but he is only indirectly the creator of what nature can produce.

"The end that God has proposed to himself in creating matter, which forms the basis of all bodies, and nature, which divides (divise) this matter, forms the bodies, makes them vary, modifies them, changes them, and renews them in different ways, can be easily known to us; for the Supreme Being cannot meet with any obstacle to his will in the execution of his works; the general results of these works are necessarily the object he had in view. Thus this end could be no other than the existence of nature, of which matter alone forms the sphere, and should not be that causing the creation of any special being.

"Do we find in the two objects created, i.e., matter and nature, the source of the good and evil which have almost always been thought to exist in the events of this world? To this question I shall answer that good and evil are only relative to particular objects, that they never affect by their temporary existence the general result expected (prevu), and that for the end which the Creator designed, there is in reality neither good nor evil, because everything in nature perfectly fulfils its object.

"Has God limited his creations to the existence of only matter and nature? This question is vain, and should remain without an answer on our part; because, being reduced to knowing anything only through observation, and to bodies alone, also to what concerns them, these being for us the only observable objects, it would be rash to speak affirmatively or negatively on this subject.

"What is a spiritual being? It is what, with the aid of the imagination, one would naturally suppose (l'on vaudra supposer). Indeed, it is only by means of opposing that which is material that we can form the idea of spirit; but as this hypothetical being is not in the category of objects which it is possible for us to observe, we do not know how to take cognizance of it. The idea that we have of it is absolutely without base.

"We only know physical objects and only objects relative to these beings (etres): such is the condition of our nature. If our thoughts, our reasonings, our principles have been considered as metaphysical objects, these objects, then, are not beings (etres). They are only relations or consequences of relations (rapports), or only results of observed laws.

"We know that relations are distinguished as general and special. Among these last are regarded those of nature, form, dimension, solidity, size, quantity, resemblance, and difference; and if we add to these objects the being observed and the consideration of known laws, as also that of conventional objects, we shall have all the materials on which our thoughts are based.

"Thus being able to observe only the phenomena of nature, as well as the laws which regulate these phenomena, also the products of these last, in a word, only bodies (corps) and what concerns them, all that which immediately proceeds from supreme power is incomprehensible to us, as it itself [i.e., supreme power] is to our minds. To create, or to make anything out of nothing, this is an idea we cannot conceive of, for the reason that in all that we can know, we do not find any model which represents it. GOD alone, then, can create, while nature can only produce. We must suppose that, in his creations, the Divinity is not restricted to the use of any time, while, on the other hand, nature can effect nothing without the aid of long periods of time."

Without translating more of this remarkable book, which is very rare, much less known than the Philosophie zoologique, the spirit of the remainder may be imagined from the foregoing extracts.

The author refers to the numerous evils resulting from ignorance, false knowledge, lack of judgment, abuse of power, demonstrating the necessity of our confining ourselves within the circle of the objects presented by nature, and never to go beyond them if we do not wish to fall into error, because the profound study of nature and of the organization of man alone, and the exact observation of facts alone, will reveal to us "the truths most important for us to know," in order to avoid the vexations, the perfidies, the injustices, and the oppressions of all sorts, and "incalculable disorders" which arise in the social body. In this way only shall we discover and acquire the means of obtaining the enjoyment of the advantages which we have a right to expect from our state of civilization. The author endeavors to state what science can and should render to society. He dwells on the sources from which man has drawn the knowledge which he possesses, and from which he can obtain many others—sources the totality of which constitutes for him the field of realities.

Lamarck also in this work has built up a system for moral philosophy.

Self-love, he says, perfectly regulated, gives rise:

1. To moral force which characterizes the laborious man, so that the length and difficulties of a useful work do not repel him.

2. To the courage of him who, knowing the danger, exposes himself when he sees that this would be useful.

3. To love of wisdom.

Wisdom, according to Lamarck, consists in the observance of a certain number of rules or virtues. These we cite in a slightly abridged form.

Love of truth in all things; the need of improving one's mind; moderation in desires; decorum in all actions; a wise reserve in unessential wants; indulgence, toleration, humanity, good will towards all men; love of the public good and of all that is necessary to our fellows; contempt for weakness; a kind of severity towards one's self which preserves us from that multitude of artificial wants enslaving those who give up to them; resignation and, if possible, moral impassibility in suffering reverses, injustices, oppression, and losses; respect for order, for public institutions, civil authorities, laws, morality, and religion.

The practice of these maxims and virtues, says Lamarck, characterizes true philosophy.

And it may be added that no one practised these virtues more than Lamarck. Like Cuvier's, his life was blameless, and though he lived a most retired life, and was not called upon to fill any public station other than his chair of zooelogy at the Jardin des Plantes, we may feel sure that he had the qualities of courage, independence, and patriotism which would have rendered such a career most useful to his country.

As Bourguin eloquently asserts: "Lamarck was the brave man who never deserted a dangerous post, the laborious man who never hesitated to meet any difficulty, the investigating spirit, firm in his convictions, tolerant of the opinions of others, the simple man, moderate in all things, the enemy of weakness, devoted to the public good, imperturbable under the attaints of fortune, of suffering, and of unjust and passionate attacks."


[198] Mathias Duval: "Le transformiste francais Lamarck," Bulletin de la Societe d'Anthropologie de Paris, xii., 1889, p. 345.

[199] Philosophie zoologique, p. 56.

[200] Loc. cit., i., p. 113.

[201] Loc. cit., i., p. 361.

[202] Loc. cit., ii., p. 465.

[203] Systeme analytique des Connaissances de l'Homme, etc.



Since the appearance of Darwin's Origin of Species, and after the great naturalist had converted the world to a belief in the general doctrine of evolution, there has arisen in the minds of many working naturalists a conviction that natural selection, or Darwinism as such, is only one of other evolutionary factors; while there are some who entirely reject the selective principle. Darwin, moreover, assumed a tendency to fortuitous variation, and did not attempt to explain its cause. Fully persuaded that he had discovered the most efficient and practically sole cause of the origin of species, he carried the doctrine to its extreme limits, and after over twenty years of observation and experiment along this single line, pushing entirely aside the Erasmus-Darwin and Lamarckian factors of change of environment, though occasionally acknowledging the value of use and disuse, he triumphantly broke over all opposition, and lived to see his doctrine generally accepted. He had besides the support of some of the strongest men in science: Wallace in a twin paper advocated the same views; Spencer, Lyell, Huxley, Hooker, Haeckel, Bates, Semper, Wyman, Gray, Leidy, and other representative men more or less endorsed Darwin's views, or at least some form of evolution, and owing largely to their efforts in scientific circles and in the popular press, the doctrine of descent rapidly permeated every avenue of thought and became generally accepted.

Meanwhile, the general doctrine of evolution thus proved, and the "survival of the fittest" an accomplished fact, the next step was to ascertain "how," as Cope asked, "the fittest originated?" It was felt by some that natural selection alone was not adequate to explain the first steps in the origin of genera, families, orders, classes, and branches or phyla. It was perceived by some that natural selection by itself was not a vera causa, an efficient agent, but was passive, and rather expressed the results of the operations of a series of factors. The transforming should naturally precede the action of the selective agencies.

We were, then, in our quest for the factors of organic evolution, obliged to fall back on the action of the physico-chemical forces such as light, or its absence, heat, cold, change of climate; and the physiological agencies of food, or in other words on changes in the physical environment, as well as in the biological environment. Lamarck was the first one who, owing to his many years' training in systematic botany and zooelogy, and his philosophic breadth, had stated more fully and authoritatively than any one else the results of changes in the action of the primary factors of evolution. Hence a return on the part of many in Europe, and especially in America, to Lamarckism or its modern form, Neolamarckism. Lamarck had already, so far as he could without a knowledge of modern morphology, embryology, cytology, and histology, suggested those fundamental principles of transformism on which rests the selective principle.

Had his works been more accessible, or, where available, more carefully read, and his views more fairly represented; had he been favored in his lifetime by a single supporter, rather than been unjustly criticised by Cuvier, science would have made more rapid progress, for it is an axiomatic truth that the general acceptance of a working evolutionary theory has given a vast impetus to biology.

We will now give a brief historical summary of the history of opinion held by Lamarckians regarding the causes of the "origin of the fittest," the rise of variations, and the appearance of a population of plant and animal forms sufficiently extensive and differentiated to allow for the play of the competitive forces, and of the more passive selective agencies which began to operate in pre-cambrian times, or as soon as the earth became fitted for the existence of living beings.

The first writer after Lamarck to work along the lines he laid down was Mr. Herbert Spencer. In 1866-71, in his epochal and remarkably suggestive Principles of Biology, the doctrine of use and disuse is implicated in his statements as to the effects of motion on structure in general;[204] and in his theory as to the origin of the notochord, and of the segmentation of the vertebral column and the segmental arrangement of the muscles by muscular strains,[205] he laid the foundations for future work along this line. He also drew attention in the same work to the complementary development of parts, and likewise instanced the decreased size of the jaws in the civilized races of mankind, as a change not accounted for by the natural selection of favorable variations.[206] In fact, this work is largely based on the Lamarckian principles, as affording the basis for the action of natural selection, and thirty years later we find him affirming: "The direct action of the medium was the primordial factor of organic evolution."[207] In his well-known essay on "The Inadequacy of Natural Selection" (1893) the great philosopher, with his accustomed vigor and force, criticises the arguments of those who rely too exclusively on Darwinism alone, and especially Neodarwinism, as a sufficient factor to account for the origin of special structures as well as species.

The first German author to appreciate the value of the Lamarckian factors was that fertile and comprehensive philosopher and investigator Ernst Haeckel, who also harmonized Lamarckism and Darwinism in these words:

"We should, on account of the grand proofs just enumerated, have to adopt Lamarck's Theory of Descent for the explanation of biological phenomena, even if we did not possess Darwin's Theory of Selection. The one is so completely and directly proved by the other, and established by mechanical causes, that there remains nothing to be desired. The laws of Inheritance and Adaptation are universally acknowledged physiological facts, the former traceable to propagation, the latter to the nutrition of organisms. On the other hand, the struggle for existence is a biological fact, which with mathematical necessity follows from the general disproportion between the average number of organic individuals and the numerical excess of their germs."[208]

A number of American naturalists at about the same date, as the result of studies in different directions, unbiassed by a too firm belief in the efficacy of natural selection, and relying on the inductive method alone, worked away at the evidence in favor of the primary factors of evolution along Lamarckian lines, though quite independently, for at first neither Hyatt nor Cope had read Lamarck's writings.

In 1866 Professor A. Hyatt published the first of a series of classic memoirs on the genetic relations of the fossil cephalopods. His labors, so rich in results, have now been carried on for forty years, and are supplemented by careful, prolonged work on the sponges, on the tertiary shells of Steinheim, and on the land shells of the Hawaiian Islands.

His first paper was on the parallelism between the different stages of life in the individual and those of the ammonites, carrying out D'Orbigny's discovery of embryonic, youthful, adult, and old-age stages in ammonites,[209] and showing that these forms are due to an acceleration of growth in the mature forms, and a retardation in the senile forms.

In a memoir on the "Biological Relations of the Jurassic Ammonites,"[210] he assigns the causes of the progressive changes in these forms, the origination of new genera, and the production of young, mature, and senile forms to "the favorable nature of the physical surroundings, primarily producing characteristic changes which become perpetuated and increased by inheritance within the group."

The study of the modifications of the tertiary forms of Planorbis at Steinheim, begun by Hilgendorf, led among others (nine in all) to the following conclusions:

"First, that the unsymmetrical spiral forms of the shells of these and of all the Mollusca probably resulted from the action of the laws of heredity, modified by gravitation.

"Second, that there are many characteristics in these shells and in other groups, which are due solely to the uniform action of the physical influence of the immediate surroundings, varying with every change of locality, but constant and uniform within each locality.

"Third, that the Darwinian law of Natural Selection does not explain these relations, but applies only to the first stages in the establishment of the differences between forms or species in the same locality. That its office is to fix these in the organization and bring them within the reach of the laws of heredity."

These views we find reiterated in his later palaeontological papers. Hyatt's views on acceleration were adopted by Neumayr.[211] Waagen,[212] from his studies on the Jurassic cephalopods, concludes that the factors in the evolution of these forms were changes in external conditions, geographical isolation, competition, and that the fundamental law was not that of Darwin, but "the law of development." Hyatt has also shown that at first evolution was rapid. "The evolution is a purely mechanical problem in which the action of the habitat is the working agent of all the major changes; first acting upon the adult stages, as a rule, and then through heredity upon the earlier stages in successive generations." He also shows that as the primitive forms migrated and occupied new, before barren, areas, where they met with new conditions, the organisms "changed their habits and structures rapidly to accord with these new conditions."[213]

While the palaeontological facts afford complete and abundant proofs of the modifying action of changes in the environment, Hyatt, in 1877, from his studies on sponges,[214] shows that the origin of their endless forms "can only be explained by the action of physical surroundings directly working upon the organization and producing by such direct action the modifications or common variations above described."

Mr. A. Agassiz remarks that the effect of the nature of the bottom of the sea on sponges and rhizopods "is an all-important factor in modifying the organism."[215]

While Hyatt's studies were chiefly on the ammonites, molluscs, and existing sponges, Cope was meanwhile at work on the batrachians. His Origin of Genera appeared shortly after Hyatt's first paper, but in the same year (1866). This was followed by a series of remarkably suggestive essays based on his extensive palaeontological work, which are in part reprinted in his Origin of the Fittest (1887); while in his epoch-making book, The Primary Factors of Organic Evolution (1896), we have in a condensed shape a clear exposition of some of the Lamarckian factors in their modern Neolamarckian form.

In the Introduction, p. 9, he remarks:

"In these papers by Professor Hyatt and myself is found the first attempt to show by concrete examples of natural taxonomy that the variations that result in evolution are not multifarious or promiscuous, but definite and direct, contrary to the method which seeks no origin for variations other than natural selection. In other words, these publications constitute the first essays in systematic evolution that appeared. By the discovery of the paleontologic succession of modifications of the articulations of the vertebrate, and especially mammalian, skeleton, I first furnished an actual demonstration of the reality of the Lamarckian factor of use, or motion, as friction, impact, and strain, as an efficient cause of evolution."[216]

The discussion in Cope's work of kinetogenesis, or of the effects of use and disuse, affords an extensive series of facts in support of these factors of Lamarck's. As these two books are accessible to every one, we need only refer the reader to them as storehouses of facts bearing on Neolamarckism.

The present writer, from a study of the development and anatomy of Limulus and of Arthropod ancestry, was early (1870)[217] led to adopt Lamarckian views in preference to the theory of Natural Selection, which never seemed to him adequate or sufficiently comprehensive to explain the origin of variations.

In the following year,[218] from a study of the insects and other animals of Mammoth Cave, we claimed that "the characters separating the genera and species of animals are those inherited from adults, modified by their physical surroundings and adaptations to changing conditions of life, inducing certain alterations in parts which have been transmitted with more or less rapidity, and become finally fixed and habitual."

In an essay entitled "The Ancestry of Insects"[219] (1873) we adopted the Lamarckian factors of change of habits and environment, of use and disuse, to account for the origin of the appendages, while we attributed the origin of the metamorphoses of insects to change of habits or of the temperature of the seasons and of climates, particularly the change in the earth's climates from the earlier ages of the globe, "when the temperature of the earth was nearly the same the world over, to the times of the present distribution of heat and cold in zones."

From further studies on cave animals, published in 1877,[220] we wrote as follows:

"In the production of these cave species, the exceptional phenomena of darkness, want of sufficient food, and unvarying temperature, have been plainly enough verae causae. To say that the principle of natural selection accounts for the change of structure is no explanation of the phenomena; the phrase has to the mind of the writer no meaning in connection with the production of these cave forms, and has as little meaning in accounting for the origination of species and genera in general. Darwin's phrase 'natural selection,' or Herbert Spencer's term 'survival of the fittest,' expresses simply the final result, while the process of the origination of the new forms which have survived, or been selected by nature, is to be explained by the action of the physical environments of the animals coupled with inheritance-force. It has always appeared to the writer that the phrases quoted above have been misused to state the cause, when they simply express the result of the action of a chain of causes which we may, with Herbert Spencer, call the 'environment' of the organism undergoing modification; and thus a form of Lamarckianism, greatly modified by recent scientific discoveries, seems to meet most of the difficulties which arise in accounting for the origination of species and higher groups of organisms. Certainly 'natural selection' or the 'survival of the fittest' is not a vera causa, though the 'struggle for existence' may show us the causes which have led to the preservation of species, while changes in the environment of the organism may satisfactorily account for the original tendency to variation assumed by Mr. Darwin as the starting-point where natural selection begins to act."

In our work on The Cave Animals of North America,[221] after stating that Darwin in his Origin of Species attributed the loss of eyes "wholly to disuse," remarking (p. 142) that after the more or less perfect obliteration of the eyes, "natural selection will often have effected other changes, such as an increase in the length of the antennae or palpi, as a compensation for blindness," we then summed up as follows the causes of the production of cave faunae in general:

"1. Change in environment from light, even partial, to twilight or total darkness, and involving diminution of food, and compensation for the loss of certain organs by the hypertrophy of others.

"2. Disuse of certain organs.

"3. Adaptation, enabling the more plastic forms to survive and perpetuate their stock.

"4. Isolation, preventing intercrossing with out-of-door forms, thus insuring the permanency of the new varieties, species, or genera.

"5. Heredity, operating to secure for the future the permanence of the newly originated forms as long as the physical conditions remain the same.

"Natural selection perhaps expresses the total result of the working of these five factors rather than being an efficient cause in itself, or at least constitutes the last term in a series of causes. Hence Lamarckism in a modern form, or as we have termed it, Neolamarckism, seems to us to be nearer the truth than Darwinism proper or natural selection."[222]

In an attempt to apply Lamarck's principle of the origin of the spines and horns of caterpillars and other insects as well as other animals to the result of external stimuli,[223] we had not then read what he says on the subject. (See p. 316.) Having, however, been led to examine into the matter, from the views held by recent observers, especially Henslow, and it appearing that Lamarck was substantially correct in supposing that the blood (his "fluids") would flow to parts on the exposed portions of the body and thus cause the origin of horns, on the principle of the saying, "ubi irritatio, ibi affluxus," we came to the following conclusions:

"The Lamarckian factors (1) change (both direct and indirect) in the milieu, (2) need, and (3) habit, and the now generally adopted principle that a change of function induces change in organs,[224] and in some or many cases actually induces the hypertrophy and specialization of what otherwise would be indifferent parts or organs;—these factors are all-important in the evolution of the colors, ornaments, and outgrowths from the cuticle of caterpillars."

Our present views as to the relations between the Lamarckian factors and the Darwinian one of natural selection are shown by the following summary at the end of this essay.

"1. The more prominent tubercles, and spines or bristles arising from them, are hypertrophied piliferous warts, the warts, with the seta or hair which they bear, being common to all caterpillars.

"2. The hypertrophy or enlargement was probably [we should rather say possibly] primarily due to a change of station from herbs to trees, involving better air, a more equable temperature, perhaps a different and better food.

"3. The enlarged and specialized tubercles developed more rapidly on certain segments than on others, especially the more prominent segments, because the nutritive fluids would tend more freely to supply parts most exposed to external stimuli.

"4. The stimuli were in great part due to the visits of insects and birds, resulting in a mimicry of the spines and projections on the trees; the colors (lines and spots) were due to light or shade, with the general result of protective mimicry, or adaptation to tree-life.

"5. As the result of some unknown factor some of the hypodermic cells at the base of the spines became in certain forms specialized so as to secrete a poisonous fluid.

"6. After such primitive forms, members of different families, had become established on trees, a process of arboreal segregation or isolation would set in, and intercrossing with low-feeders would cease.

"7. Heredity, or the unknown factors of which heredity is the result, would go on uninterruptedly, the result being a succession of generations perfectly adapted to arboreal life.

"8. Finally the conservative agency of natural selection operates constantly, tending towards the preservation of the new varieties, species, and genera, and would not cease to act, in a given direction, so long as the environment remained the same.

"9. Thus in order to account for the origin of a species, genus, family, order, or even a class, the first steps, causing the origination of variations, were in the beginning due to the primary (direct and indirect) factors of evolution (Neolamarckism), and the final stages were due to the secondary factors, segregation and natural selection (Darwinism)."

From a late essay[225] we take the following extracts explaining our views:

"In seeking to explain the causes of a metamorphosis in animals, one is compelled to go back to the primary factors of organic evolution, such as the change of environment, whether the factors be cosmical (gravity), physical changes in temperature, effects of increased or diminished light and shade, under- or over-nutrition, and the changes resulting from the presence or absence of enemies, or from isolation. The action of these factors, whether direct or indirect, is obvious, when we try to explain the origin or causes of the more marked metamorphoses of animals. Then come in the other Lamarckian factors of use and disuse, new needs resulting in new modes of life, habits, or functions, which bring about the origination, development, and perfection of new organs, as in new species and genera, etc., or which in metamorphic forms may result in a greater increase in the number of, and an exaggeration of the features characterizing the stages of larval life.

"VI. The Adequacy of Neolamarckism.

"It is not to be denied that in many instances all through the ceaseless operation of these fundamental factors there is going on a process of sifting or of selection of forms best adapted to their surroundings, and best fitted to survive, but this factor, though important, is quite subordinate to the initial causes of variation, and of metamorphic changes.

"Neolamarckism,[226] as we understand this doctrine, has for its foundation a combination of the factors suggested by the Buffon and Geoffroy St. Hilaire school, which insisted on the direct action of the milieu, and of Lamarck, who relied both on the direct (plants and lowest animals) and on the indirect action of the environment, adding the important factors of need and of change of habits resulting either in the atrophy or in the development of organs by disuse or use, with the addition of the hereditary transmission of characters acquired in the lifetime of the individual.

"Lamarck's views, owing to the early date of his work, which was published in 1809, before the foundation of the sciences of embryology, cytology, palaeontology, zooegeography, and in short all that distinguishes modern biology, were necessarily somewhat crude, though the fundamental factors he suggested are those still invoked by all thinkers of Lamarckian tendencies.

"Neolamarckism gathers up and makes use of the factors both of the St. Hilaire and Lamarckian schools, as containing the more fundamental causes of variation, and adds those of geographical isolation or segregation (Wagner and Gulick), the effects of gravity, the effects of currents of air and of water, of fixed or sedentary as opposed to active modes of life, the results of strains and impacts (Ryder, Cope, and Osborn), the principle of change of function as inducing the formation of new structures (Dohrn), the effects of parasitism, commensalism, and of symbiosis—in short, the biological environment; together with geological extinction, natural and sexual selection, and hybridity.

"It is to be observed that the Neolamarckian in relying mainly on these factors does not overlook the value of natural selection as a guiding principle, and which began to act as soon as the world became stocked with the initial forms of life, but he simply seeks to assign this principle to its proper position in the hierarchy of factors.

"Natural selection, as the writer from the first has insisted, is not a vera causa, an initial or impelling cause in the origination of new species and genera. It does not start the ball in motion; it only, so to speak, guides its movements down this or that incline. It is the expression, like that of "the survival of the fittest" of Herbert Spencer, of the results of the combined operation of the more fundamental factors. In certain cases we cannot see any room for its action; in some others we cannot at present explain the origin of species in any other way. Its action increased in proportion as the world became more and more crowded with diverse forms, and when the struggle for existence had become more unceasing and intense. It certainly cannot account for the origination of the different branches, classes, or orders of organized beings. It in the main simply corresponds to artificial selection; in the latter case, man selects forms already produced by domestication, the latter affording sports and varieties due to change in the surroundings, that is, soil, climate, food, and other physical features, as well as education.

"In the case also of heredity, which began to operate as soon as the earliest life forms appeared, we have at the outset to invoke the principle of the heredity of characters acquired during the lifetime of lowest organisms.

"Finally, it is noticeable that when one is overmastered by the dogma of natural selection he is apt, perhaps unconsciously, to give up all effort to work out the factors of evolution, or to seek to work out this or that cause of variation. Trusting too implicitly to the supposed vera causa, one may close his eyes to the effects of change of environment or to the necessity of constant attempts to discover the real cause of this or that variation, the reduction or increase in size of this or that organ; or become insensible to the value of experiments. Were the dogma of natural selection to become universally accepted, further progress would cease, and biology would tend to relapse into a stage of atrophy and degeneration. On the other hand, a revival of Lamarckism in its modern form, and a critical and doubting attitude towards natural selection as an efficient cause, will keep alive discussion and investigation, and especially, if resort be had to experimentation, will carry up to a higher plane the status of philosophical biology."

Although now the leader of the Neodarwinians, and fully assured of the "all-sufficiency" of natural selection, the veteran biologist Weismann, whose earlier works were such epoch-making contributions to insect embryology, was, when active as an investigator, a strong advocate of the Lamarckian factors. In his masterly work, Studies in the Theory of Descent[227] (1875), although accepting Darwin's principle of natural selection, he also relied on "the transforming influence of direct action as upheld by Lamarck," although he adds, "its extent cannot as yet be estimated with any certainty." He concluded from his studies in seasonal dimorphism, "that differences of specific value can originate through the direct action of external conditions of life only." While conceding that sexual selection plays a very important part in the markings and coloring of butterflies, he adds "that a change produced directly by climate may be still further increased by sexual selection." He also inquired into the origin of variability, and held that it can be elucidated by seasonal dimorphism. He thus formulated the chief results of his investigations: "A species is only caused to change through the influence of changing external conditions of life, this change being in a fixed direction which entirely depends on the physical nature of the varying organism, and is different in different species or even in the two sexes of the same species."

The influence of changes of climate on variation has been studied to especial advantage in North America, owing to its great extent, and to the fact that its territory ranges from the polar to the tropical regions, and from the Atlantic to the Pacific Ocean. As respects climatic variation in birds, Professor Baird first took up the inquiry, which was greatly extended, with especial relation to the formation of local varieties, by Dr. J. A. Allen,[228] who was the first to ascertain by careful measurements, and by a study of the difference in plumage and pelage of individuals inhabiting distant portions of a common habitat, the variations due to climatic and local causes.

"That varieties," he says, "may and do arise by the action of climatic influences, and pass on to become species; and that species become, in like manner, differentiated into genera, is abundantly indicated by the facts of geographical distribution, and the obvious relation of local forms to the conditions of environment. The present more or less unstable condition of the circumstances surrounding organic beings, together with the known mutations of climate our planet has undergone in past geological ages, point clearly to the agency of physical conditions as one of the chief factors in the evolution of new forms of life. So long as the environing conditions remain stable, just so long will permanency of character be maintained; but let changes occur, however gradual or minute, and differentiations begin." He inclines to regard the modifications as due rather to the direct action of the conditions of environment than to "the round-about process of natural selection." He also admits that change of habits and food, use and disuse, are factors.

The same kind of inquiry, though on far less complete data, was extended by the present writer[229] in 1873 to the moths, careful measurements of twenty-five species of geometrid moths common to the Atlantic and Pacific coasts of North America showing that there is an increase in size and variation in shape of the wings, and in some cases in color, in the Pacific Coast over Eastern or Atlantic Coast individuals of the same species, the differences being attributed to the action of climatic causes. The same law holds good in the few Notodontian moths common to both sides of our continent. Similar studies, the results depending on careful measurements of many individuals, have recently been made by C. H. Eigenmann (1895-96), W. J. Moenkhaus (1896), and H. C. Bumpus (1896-98).

The discoveries of Owen, Gaudry, Huxley, Kowalevsky, Cope, Marsh, Filhol, Osborn, Scott, Wortmann, and many others, abundantly prove that the lines of vertebrate descent must have been the result of the action of the primary factors of organic evolution, including the principles of migration, isolation, and competition; the selective principle being secondary and preservative rather than originative.

Important contributions to dynamic evolution or kinetogenesis are the essays of Cope, Ryder, Dall, Osborn, Jackson, Scott, and Wortmann.

Ryder began in 1877 to publish a series of remarkably suggestive essays on the "mechanical genesis," through strains, of the vertebrate limbs and teeth, including the causes of the reduction of digits. In discussing the origin of the great development of the incisor teeth of rodents, he suggested that "the more severe strains to which they were subjected by enforced or intelligently assumed changes of habit, were the initiatory agents in causing them to assume their present forms, such forms as were best adapted to resist the greatest strains without breaking."[230]

He afterwards[231] claimed that the articulations of the cartilaginous fin-rays of the trout (Salmo fontinalis) are due to the mechanical strains experienced by the rays in use as motors of the body of the fish in the water.

In the line of inquiry opened up by Cope and by Ryder are the essays of Osborn[232] on the mechanical causes for the displacement of the elements of the feet in the mammals, and the phylogeny of the teeth. Also Professor W. B. Scott thus expresses the results of his studies:[233]

"To sum up the results of our examination of certain series of fossil mammals, one sees clearly that transformation, whether in the way of the addition of new parts or the reduction of those already present, acts just as if the direct action of the environment and the habits of the animal were the efficient cause of the change, and any explanation which excludes the direct action of such agencies is confronted by the difficulty of an immense number of the most striking coincidences.... So far as I can see, the theory of determinate variations and of use-inheritance is not antagonistic but supplementary to natural selection, the latter theory attempting no explanation of the causes of variation. Nor is it pretended for a moment that use and disuse are the sole or even the chief factors in variation."

As early as 1868 the Lamarckian factor of isolation, due to migration into new regions, was greatly extended, and shown by Moritz Wagner[234] to be a most important agent in the limitation and fixation of varieties and species.

"Darwin's work," he says, "neither satisfactorily explains the external cause which gives the first impulse to increased individual variability, and consequently to natural selection, nor that condition which, in connection with a certain advantage in the struggle for life, renders the new characteristics indispensable. The latter is, according to my conviction, solely fulfilled by the voluntary or passive migration of organisms and colonization, which depends in a great measure upon the configuration of the country; so that only under favorable conditions would the home of a new species be founded."

This was succeeded by Rev. J. T. Gulick's profound essays "On Diversity of Evolution under One Set of External Conditions"[235] (1872), and on "Divergent Evolution through Cumulative Segregation"[236] (1887).

These and later papers are based on his studies on the land shells of the Hawaiian Islands. The cause of their extreme diversity of local species is, he claims, not due to climatic conditions, food, enemies, or to natural selection, but to the action of what he calls the "law of segregation."

Fifteen years later Mr. Romanes published his theory of physiological selection, which covered much the same ground.

A very strong little book by an ornithologist of wide experience, Charles Dixon,[237] and refreshing to read, since it is packed with facts, is Lamarckian throughout. The chief factor in the formation of local species is, he thinks, isolation; the others are climatic influences (especially the glacial period), use and disuse, and sexual selection as well as chemical agency. Dixon insists on the "vast importance of isolation in the modification of many forms of life, without the assistance of natural selection." Again he says: "Natural selection, as has often been remarked, can only preserve a beneficial variation—it cannot originate it, it is not a cause of variation; on the other hand, the use or disuse of organs is a direct cause of variation, and can furnish natural selection with abundance of material to work upon" (p. 49). The book, like the papers of Allen, Ridgway, Gulick, and others, shows the value of isolation or segregation in special areas as a factor in the origination of varieties and species, the result being the prevention of interbreeding, which would otherwise swamp the incipient varieties.

Here might be cited Delboeuf's law:[238]

"When a modification is produced in a very small number of individuals, this modification, even were it advantageous, would be destroyed by heredity, as the favored individuals would be obliged to unite with the unmodified individuals. Il n'en est rien, cependant. However great may be the number of forms similar to it, and however small may be the number of dissimilar individuals which would give rise to an isolated individual, we can always, while admitting that the different generations are propagated under the same conditions, meet with a number of generations at the end of which the sum total of the modified individuals will surpass that of the unmodified individuals." Giard adds that this law is capable of mathematical demonstration. "Thus the continuity or even the periodicity of action of a primary factor, such, for example, as a variation of the milieu, shows us the necessary and sufficient condition under which a variety or species originates without the aid of any secondary factor."

Semper,[239] an eminent zooelogist and morphologist, who also was the first (in 1863) to criticise Darwin's theory of the mode of formation of coral atolls, though not referring to Lamarck, published a strong, catholic, and original book, which is in general essentially Lamarckian, while not undervaluing Darwin's principle of natural selection. "It appears to me," he says, in the preface, "that of all the properties of the animal organism, Variability is that which may first and most easily be traced by exact investigation to its efficient causes."

"By a rearrangement of the materials of his argument, however, we obtain, as I conceive, convincing proof that external conditions can exert not only a very powerful selective force, but a transforming one as well, although it must be the more limited of the two.

"An organ no longer needed for its original purpose may adapt itself to the altered circumstances, and alter correspondingly if it contains within itself, as I have explained above, the elements of such a change. Then the influence exerted by the changed conditions will be transforming, not selective.

"This last view may seem somewhat bold to those readers who know that Darwin, in his theory of selection, has almost entirely set aside the direct transforming influence of external circumstances. Yet he seems latterly to be disposed to admit that he had undervalued the transforming as well as the selective influence of external conditions; and it seems to me that his objection to the idea of such an influence rested essentially on the method of his argument, which seemed indispensable for setting his theory of selection and his hypothesis as to the transformation of species in a clear light and on a firm footing" (p. 37).

Dr. H. de Varigny has carried on much farther the kind of experiments begun by Semper. In his Experimental Evolution he employs the Lamarckian factors of environment and use and disuse, regarding the selective factors as secondary.

The Lamarckian factors are also depended upon by the late Professor Eimer in his works on the variation of the wall-lizard and on the markings of birds and mammals (1881-88), his final views being comprised in his general work.[240] The essence of his point of view may be seen by the following quotation:

"According to my conception, the physical and chemical changes which organisms experience during life through the action of the environment, through light or want of light, air, warmth, cold, water, moisture, food, etc., and which they transmit by heredity, are the primary elements in the production of the manifold variety of the organic world, and in the origin of species. From the materials thus supplied the struggle for existence makes its selection. These changes, however, express themselves simply as growth" (p. 22).

In a later paper[241] Eimer proposes the term "orthogenesis," or direct development, in rigorous conformity to law, in a few definite directions. Although this is simply and wholly Lamarckism, Eimer claims that it is not, "for," he strangely enough says, "Lamarck ascribed no efficiency whatever to the effects of outward influences on the animal body, and very little to their effects upon vegetable organisms." Whereas if he had read his Lamarck carefully, he would have seen that the French evolutionist distinctly states that the environment acts directly on plants and the lower animals, but indirectly on those animals with a brain, meaning the higher vertebrates. The same anti-selection views are held by Eimer's pupil, Piepers,[242] who explains organic evolution by "laws of growth, ... uncontrolled by any process of selection."

Dr. Cunningham likewise, in the preface to his translation of Eimer's work, gives his reasons for adopting Neolamarckian views, concluding that "the theory of selection can never get over the difficulty of the origin of entirely new characters;" that "selection, whether natural or artificial, could not be the essential cause of the evolution of organisms." In an article on "The New Darwinism" (Westminster Review, July, 1891) he claims that Weismann's theory of heredity does not explain the origin of horns, venomous teeth, feathers, wings of insects, or mammary glands, phosphorescent organs, etc., which have arisen on animals whose ancestors never had anything similar.

Discussing the origin of whales and other aquatic mammals, W. Kuekenthal suggests that the modifications are partially attributable to mechanical principles. (Annals and Mag. Nat. Hist., February, 1891.)

From his studies on the variation of butterflies, Karl Jordan[243] proposes the term "mechanical selection" to account for them, but he points out that this factor can only work on variations produced by other factors. Certain cases, as the similar variation in the same locality of two species of different families, but with the same wing pattern, tell in favor of the direct action of the local surroundings on the markings of the wings.

In the same direction are the essays of Schroeder[244] on the markings of caterpillars, which he ascribes to the colors of the surroundings; of Fischer[245] on the transmutations of butterflies as the result of changes of temperature, and also Dormeister's[246] earlier paper. Steinach[247] attributes the color of the lower vertebrates to the direct influence of the light on the pigment cells, as does Biedermann.[248]

In his address on evolution and the factors of evolution, Professor A. Giard[249] has given due credit to Lamarck as "the creator of transformism," and to the position to be assigned to natural selection as a secondary factor. He quotes at length Lamarck's views published in 1806. After enumerating the primary factors of organic evolution, he places natural selection among his secondary factors, such as heredity, segregation, amixia, etc. On the other hand, he states that Lamarck was not happy in the choice of the examples which he gave to explain the action of habits and use of parts. "Je ne rappellerai par l'histoire tant de fois critique du cou de la giraffe et des cornes de l'escargot."

Another important factor in the evolution of the metazoa or many-celled animals, from the sponges and polyps upward from the one-celled forms or protozoa, is the principle of animal aggregation or colonization advanced by Professor Perrier. As civilization and progressive intelligence in mankind arose from the aggregation of men into tribes or peoples which lived a sedentary life, so the agricultural, building, and other arts forthwith sprang up; and as the social insects owe their higher degree of intelligence to their colonial mode of life, so as soon as unicellular organisms began to become fixed, and form aggregates, the sponge and polyp types of organization resulted, this leading to the gastraea, or ancestral form from which all the higher phyla may have originated.

M. Perrier appears to fully accept Lamarck's views, including his speculations as to wants, and use and disuse. He, however, refuses to accept Lamarck's extreme view as to the origin through effort of entirely new organs. As he says: "Unfortunately, if Lamarck succeeded in explaining in a plausible way the modification of organs already existing, their adaptation to different uses, or even their disappearance from disuse, in regard to the appearance of new organs he made hypotheses so venturesome that they led to the momentary forgetfulness of his other forceful conceptions."[250]

The popular idea of Lamarckism, and which from the first has been prejudicial to his views, is that an animal may acquire an organ by simply wishing for or desiring it, or, as his French critics put it, "Un animal finit toujours par posseder un organe quand il le veut." "Such," says Perrier,[251] "is not the idea of Lamarck, who simply attributes the transformations of species to the stimulating action of external conditions, construing it under the expression of wants (besoins), and explaining by that word what we now call adaptations. Thus the long neck of the giraffe results from the fact that the animal inhabits a country where the foliage is situated at the tops of high trees; the long legs of the wading birds have originated from the fact that these birds are obliged to seek their food in the water without wetting themselves," etc. (See p. 350.)

"Many cases," says Perrier, "may be added to-day to those which Lamarck has cited to support his first law [pp. 303, 346]; the only point which is open to discussion is the extent of the changes which an organ may undergo, through the use it is put to by the animal. It is a simple question of measurement. The possibility of the creation of an organ in consequence of external stimuli is itself a matter which deserves to be studied, and which we have no right to reject without investigation, without observations, or to treat as a ridiculous dream; Lamarck would doubtless have made it more readily accepted, if he had not thought it well to pass over the intermediate steps by means of wants. It is incontestable that by lack of exercise organs atrophy and disappear."

Finally, says Perrier: "Without doubt the real mechanism of the improvement (perfectionnement) of organisms has escaped him [Lamarck], but neither has Darwin explained it. The law of natural selection is not the indication of a process of transformation of animals; it is the expression of the total results. It states these results without showing us how they have been brought about. We indeed see that it tends to the preservation of the most perfect organisms; but Darwin does not show us how the organisms themselves originated. This is a void which we have only during these later years tried to fill" (p. 90).

Dr. J. A. Jeffries, author of an essay "On the Epidermal System of Birds," in a later paper[252] thus frankly expresses his views as to the relations of natural selection to the Lamarckian factors. Referring to Darwin's case of the leg bones of domestic ducks compared with those of wild ducks, and the atrophy of disused organs, he adds:

"In this case, as with most of Lamarck's laws, Darwin has taken them to himself wherever natural selection, sexual selection, and the like have fallen to the ground.

"Darwin's natural selection does not depend, as is popularly supposed, on direct proof, but is adduced as an hypothesis which gains its strength from being compatible with so many facts of correlation between an organism and its surroundings. Yet the same writer who considers natural selection proved will call for positive experimental proof of Lamarck's theory, and refuse to accept its general compatibility with the facts as support. Almost any case where natural selection is held to act by virtue of advantage gained by use of a part is equally compatible with Lamarck's theory of use and development. The wings of birds of great power of flight, the relations of insects to flowers, the claws of beasts of prey, are all cases in point."

Professor J. A. Thomson's useful Synthetic Summary of the Influence of the Environment upon the Organism (1887) takes for its text Spencer's aphorism, that the direct action of the medium was the primordial factor of organic evolution. Professor Geddes relies on the changes in the soil and climate to account for the origin of spines in plants.

The botanist Sachs, in his Physiology of Plants (1887), remarks: "A far greater portion of the phenomena of life are [is] called forth by external influences than one formerly ventured to assume."

Certain botanists are now strong in the belief that the species of plants have originated through the direct influence of the environment. Of these the most outspoken is the Rev. Professor G. Henslow. His view is that self-adaptation, by response to the definite action of changed conditions of life, is the true origin of species. In 1894[253] he insisted, "in the strictest sense of the term, that natural selection is not wanted as an 'aid' or a 'means' in originating species." In a later paper[254] he reasserts that all variations are definite, that there are no indefinite variations, and that natural selection "can take no part in the origination of varieties." He quotes with approval the conclusion of Mr. Herbert Spencer in 1852, published

"seven years before Darwin and Dr. Wallace superadded natural selection as an aid in the origin of species. He saw no necessity for anything beyond the natural power of change with adaptation; and I venture now to add my own testimony, based upon upwards of a quarter of a century's observations and experiments, which have convinced me that Mr. Spencer was right and Darwin was wrong. His words are as follows: 'The supporters of the development hypothesis can show ... that any existing species, animal or vegetable, when placed under conditions different from its previous ones, immediately begins to undergo certain changes of structure fitting it for the new conditions; ... that in the successive generations these changes continue until ultimately the new conditions become the natural ones.... They can show that throughout all organic nature there is at work a modifying influence of the kind they assign as the causes of specific differences; an influence which, though slow in its action, does in time, if the circumstances demand it, produce marked changes.'"[255]

Mr. Henslow adduces observations and experiments by Buckman, Bailey, Lesage, Lothelier, Costantin, Bonnier, and others, all demonstrating that the environment acts directly on the plant.

Henslow also suggests that endogens have originated from exogenous plants through self-adaptation to an aquatic habit,[256] which is in line with our idea that certain classes of animals have diverged from the more primitive ones by change of habit, although this has led to the development of new class-characteristics by use and disuse, phenomena which naturally do not operate in plants, owing to their fixed conditions.

Other botanists—French, German, and English—have also been led to believe in the direct influence of the milieu, or environment. Such are Viet,[257] and Scott Elliot,[258] who attributes the growth of bulbs to the "direct influence of the climate."

In a recent work Costantin[259] shares the belief emphatically held by some German botanists in the direct influence of the environment not only as modifying the form, but also as impressing, without the aid of natural selection, that form on the species or part of its inherited stock; and one chapter is devoted to an attempt to establish the thesis that acquired characters are inherited.

In his essay "On Dynamic Influences in Evolution" W. H. Dall[260] holds the view that—

"The environment stands in a relation to the individual such as the hammer and anvil bear to the blacksmith's hot iron. The organism suffers during its entire existence a continuous series of mechanical impacts, none the less real because invisible, or disguised by the fact that some of them are precipitated by voluntary effort of the individual itself.... It is probable that since the initiation of life upon the planet no two organisms have ever been subjected to exactly the same dynamic influences during their development.... The reactions of the organism against the physical forces and mechanical properties of its environment are abundantly sufficient, if we are granted a single organism, with a tendency to grow, to begin with; time for the operation of the forces; and the principle of the survival of the fittest."

In his paper on the hinge of Pelecypod molluscs and its development, he has pointed out a number of the particular ways in which the dynamics of the environment may act on the characters of the hinge and shell of bivalve molluscs. He has also shown that the initiation and development of the columellar plaits in Voluta, Mitra, and other gasteropod molluscs "are the necessary mechanical result of certain comparatively simple physical conditions; and that the variations and peculiarities connected with these plaits perfectly harmonize with the results which follow within organic material subjected to analogous stresses."

In the same line of study is Dr. R. T. Jackson's[261] work on the mechanical origin of characters in the lamellibranch molluscs. "The bivalve nature of the shell doubtless arose," he says, "from the splitting on the median line of a primitive univalvular ancestor;" and he adds: "A parallel case is seen in the development of a bivalve shell in ancient crustaceans;" in both types of shells "the form is induced by the mechanical conditions of the case." The adductor muscles of bivalve molluscs and crustaceans are, he shows plainly, the necessary consequence of the bivalvular condition.

In his theory as to the origin of the siphon of the clam (Mya arenaria), he explains it in a manner identical with Lamarck's explanations of the origin of the wading and swimming birds, etc., even to the use of the words "effort" and "habit."

"In Mya arenaria we find a highly elongated siphon. In the young the siphon hardly extends beyond the borders of the valves, and then the animal lives at or close to the surface. In progressive growth, as the animal burrows deeper, the siphon elongates, until it attains a length many times the total length of the valves.

"The ontogeny of the individual and the paleontology of the family both show that Mya came from a form with a very abbreviated siphon, and it seems evident that the long siphon of this genus was brought about by the effort to reach the surface induced by the habit of deep burial."

"The tendency to equalize the form of growth in a horizontal plane, or the geomalic tendency of Professor Hyatt,[262] is seen markedly in pelecypods. In forms which crawl on the free borders of the valves, the right and left growth in relation to the perpendicular is obvious, and agrees with the right and left sides of the animal. In Pecten the animal at rest lies on the right valve, and swims or flies with the right valve lowermost. Here equalization to the right and left of the perpendicular line passing through the centre of gravity is very marked (especially in the Vola division of the group); but the induced right and left aspect corresponds to the dorsal and ventral sides of the animal, not the right and left sides, as in the former case. Lima, a near ally of Pecten, swims with the edges of the valves perpendicular. In this case the geomalic growth corresponds to the right and left sides of the animal.

"The oyster has a deep or spoon-shaped attached valve, and a flat or flatter free valve. This form, or a modification of it, we find to be characteristic of all pelecypods which are attached to a foreign object of support by the cementation of one valve. All are highly modified, and are strikingly different from the normal form seen in locomotive types of the group. The oyster may be taken as the type of the form adopted by attached pelecypods. The two valves are unequal, the attached valve being concave, the free valve flat; but they are not only unequal, they are often very dissimilar—as different as if they belonged to a distinct type in what would be considered typical forms. This is remarkable as a case of acquired and inherited characteristics finding very different expression in the two valves of a group belonging to a class typically equivalvular. The attached valve is the most highly modified, and the free is least modified, retaining more fully ancestral characters. Therefore, it is to the free young before fixation takes place and to the free, least-modified valve that we must turn in tracing genetic relations of attached groups. Another characteristic of attached pelecypods is camerated structure, which is most frequent and extensive in the thick attached valve. The form as above described is characteristic of the Ostreidae, Hinnites, Spondylus, and Plicatula, Dimya, Pernostrea, Aetheria, and Mulleria; and Chama and its near allies. These various genera, though ostreiform in the adult, are equivalvular and of totally different form in the free young. The several types cited are from widely separated families of pelecypods, yet all, under the same given conditions, adopt a closely similar form, which is strong proof that common forces acting on all alike have induced the resulting form. What the forces are that have induced this form it is not easy to see from the study of this form alone; but the ostrean form is the base of a series, from the summit of which we get a clearer view." (Amer. Nat., pp. 18-20.)

Here we see, plainly brought out by Jackson's researches, that the Lamarckian factors of change of environment and consequently of habit, effort, use and disuse, or mechanical strains resulting in the modifications of some, and even the appearance of new organs, as the adductor muscles, have originated new characters which are peculiar to the class, and thus a new class has been originated. The mollusca, indeed, show to an unusual extent the influence of a change in environment and of use and disuse in the formation of classes.

Lang's treatment, in his Text-book of Comparative Anatomy (1888), of the subjects of the musculature of worms and crustacea, and of the mechanism of the motion of the segmented body in the Arthropoda, is of much value in relation to the mechanical genesis of the body segments and limbs of the members of this type. Dr. B. Sharp has also discussed the same subject (American Naturalist, 1893, p. 89), also Graber in his works, while the present writer in his Text-book of Entomology (1898) has attempted to treat of the mechanical origin of the segments of insects, and of the limbs and their jointed structure, along the lines laid down by Herbert Spencer, Lang, Sharp, and Graber.

W. Roux[263] has inquired how natural selection could have determined the special orientation of the sheets of spongy tissue of bone. He contends that the selection of accidental variation could not originate species, because such variations are isolated, and because, to constitute a real advantage, they should rest on several characters taken together. His example is the transformation of aquatic into terrestrial animals.

G. Pfeffer[264] opposes the efficacy of natural selection, as do C. Emery[265] and O. Hertwig. The essence of Hertwig's The Biological Problem of To-day (1894) is that "in obedience to different external influences the same rudiments may give rise to different adult structures" (p. 128). Delage, in his Theories sur l'Heredite, summarizes under seven heads the objections of these distinguished biologists. Species arise, he says, from general variations, due to change in the conditions of life, such as food, climate, use and disuse, very rarely individual variations, such as sports or aberrations, which are more or less the result of disease.

Mention should also be made of the essays and works of H. Driesch,[266] De Varigny,[267] Danilewsky,[268] Verworn,[269] Davenport,[270] Gadow,[271] and others.

In his address on "Neodarwinism and Neolamarckism," Mr. Lester F. Ward, the palaeobotanist, says:

"I shall be obliged to confine myself almost exclusively to the one great mind, who far more than all others combined paved the way for the new science of biology to be founded by Darwin, namely, Lamarck." After showing that Lamarck established the functional, or what we would call the dynamic factors, he goes on to say that "Lamarck, although he clearly grasped the law of competition, or the struggle for existence, the law of adaptation, or the correspondence of the organism to the changing environment, the transmutation of species, and the genealogical descent of all organic beings, the more complex from the more simple; he nevertheless failed to conceive the selective principle as formulated by Darwin and Wallace, which so admirably complemented these great laws."[272]

As is well known, Huxley was, if we understand his expressions aright, not fully convinced of the entire adequacy of natural selection.

"There is no fault to be found with Mr. Darwin's method, then; but it is another question whether he has fulfilled all the conditions imposed by that method. Is it satisfactorily proved, in fact, that species may be originated by selection? that there is such a thing as natural selection? that none of the phenomena exhibited by species are inconsistent with the origin of species in this way?

* * * * *

"After much consideration, with assuredly no bias against Mr. Darwin's views, it is our clear conviction that, as the evidence stands, it is not absolutely proven that a group of animals, having all the characters exhibited by species in nature, has ever been originated by selection, whether artificial or natural. Groups having the morphological character of species, distinct and permanent races, in fact, have been so produced over and over again; but there is no positive evidence, at present, that any group of animals has, by variation and selective breeding, given rise to another group which was even in the least degree infertile with the first. Mr. Darwin is perfectly aware of this weak point, and brings forward a multitude of ingenious and important arguments to diminish the force of the objection."[273]

We have cited the foregoing conclusions and opinions of upwards of forty working biologists, many of whom were brought up, so to speak, in the Darwinian faith, to show that the pendulum of evolutionary thought is swinging away from the narrow and restricted conception of natural selection, pure and simple, as the sole or most important factor, and returning in the direction of Lamarckism.

We may venture to say of Lamarck what Huxley once said of Descartes, that he expressed "the thoughts which will be everybody's two or three centuries after" him. Only the change of belief, due to the rapid accumulation of observed facts, has come in a period shorter than "two or three centuries;" for, at the end of the very century in which Lamarck, whatever his crudities, vagueness, and lack of observations and experiments, published his views, wherein are laid the foundations on which natural selection rests, the consensus of opinion as to the direct and indirect influence of the environment, and the inadequacy of natural selection as an initial factor, was becoming stronger and deeper-rooted each year.

We must never forget or underestimate, however, the inestimable value of the services rendered by Darwin, who by his patience, industry, and rare genius for observation and experiment, and his powers of lucid exposition, convinced the world of the truth of evolution, with the result that it has transformed the philosophy of our day. We are all of us evolutionists, though we may differ as to the nature of the efficient causes.


[204] Vol. ii., p. 167, 1871.

[205] Vol. ii., p. 195.

[206] Vol. i., Sec. 166, p. 456.

[207] The Factors of Organic Evolution, 1895, p. 460.

[208] Schoepfungegeschichte, 1868. The History of Creation, New York, ii., p. 355.

[209] Alcide d'Orbigny, Paleontologie francaise, Paris, 1840-59.

[210] Abstract in Proceedings of the Boston Society of Natural History, xvii., December 16, 1874.

[211] Zeitschr. der deutsch. geol. Gesellschaft, 1875.

[212] Palaeontologica Indica. Jurassic Fauna of Kutch. I. Cephalopoda, pp. 242-243. (See Hyatt's Genesis of the Arietidae, pp. 27, 42.)

[213] "Genera of Fossil Cephalopods," Proc. Bost. Soc. Nat. Hist., xxii., April 4, 1883, p. 265.

[214] "Revision of the North American Poriferae." Memoirs Bost. Soc. Nat. Hist., ii., part iv., 1877.

[215] Three Cruises of the "Blake," 1888, ii., p. 158.

[216] The earliest paper in which he adopted the Lamarckian doctrines of use and effort was his "Methods of Creation of Organic Types" (1871). In this paper Cope remarks that he "has never read Lamarck in French, nor seen a statement of his theory in English, except the very slight notices in the Origin of Species and Chambers' Encyclopaedia, the latter subsequent to the first reading of this paper." It is interesting to see how thoroughly Lamarckian Cope was in his views on the descent theory.

[217] Proceedings of the American Association for the Advancement of Science, Troy meeting, 1870. Printed in August, 1871.

[218] American Naturalist, v., December, 1871, p. 750. See also pp. 751, 759, 760.

[219] Printed in advance, being chapter xiii. of Our Common Insects, Salem, 1873, pp. 172, 174, 179, 180, 181, 185.

[220] "A New Cave Fauna in Utah." Bulletin of the United States Geological Survey, iii., April 9, 1877, p. 167.

[221] Memoirs of the National Academy of Sciences, iv., 1888, pp. 156: 27 plates. See also American Naturalist, Sept., 1888, xxii., p. 808, and Sept., 1894, xxviii., p. 333.

[222] Carl H. Eigenmann, in his elaborate memoir, The Eyes of the Blind Vertebrates of North America (Archiv fuer Entwickelungsmechanik der Organismen, 1899, viii.), concludes that the Lamarckian view, that through disuse and the transmission by heredity of the characters thus inherited the eyes of blind fishes are diminished, "is the only view so far examined that does not on the face of it present serious objections" (pp. 605-609).

[223] "Hints on the Evolution of the Bristles, Spines, and Tubercles of Certain Caterpillars, etc." Proceedings Boston Society of Natural History, xxiv., 1890, pp. 493-560; 2 plates.

[224] E. J. Marey: "Le Transformisme et la Physiologie Experimentale, Cours du College de France," Revue Scientifique, 2^me serie, iv., p. 818. (Function makes the organ, especially in the osseous and muscular systems.) See also A. Dohrn: Der Ursprung der Wirbelthiere und das Princip des Functionswechsels, Leipzig, 1875. See also Lamarck's opinion, p. 295.

[225] "On the Inheritance of Acquired Characters in Animals with a Complete Metamorphosis." Proceedings Amer. Acad. Arts and Sciences, Boston, xxix. (N. S., xxi.). 1894, pp. 331-370; also monograph of "Bombycine Moths," Memoirs Nat. Acad. Sciences, vii., 1895, p. 33.

[226] In 1885, in the Introduction to the Standard Natural History, we proposed the term Neolamarckianism, or Lamarckism in its modern form, to designate the series of factors of organic evolution, and we take the liberty to quote the passage in which the word first occurs. We may add that the briefer form, Neolamarckism, is the more preferable.

"In the United States a number of naturalists have advocated what may be called Neo-Lamarckian views of evolution, especially the conception that in some cases rapid evolution may occur. The present writer, contrary to pure Darwinians, believes that many species, but more especially types of genera and families, have been produced by changes in the environment acting often with more or less rapidity on the organism, resulting at times in a new genus, or even a family type. Natural selection, acting through thousands, and sometimes millions, of generations of animals and plants, often operates too slowly; there are gaps which have been, so to speak, intentionally left by Nature. Moreover, natural selection was, as used by some writers, more an idea than a vera causa. Natural selection also begins with the assumption of a tendency to variation, and presupposes a world already tenanted by vast numbers of animals among which a struggle for existence was going on, and the few were victorious over the many. But the entire inadequacy of Darwinism to account for the primitive origin of life forms, for the original diversity in the different branches of the tree of life forms, the interdependence of the creation of ancient faunas and floras on geological revolutions, and consequent sudden changes in the environment of organisms, has convinced us that Darwinism is but one of a number of factors of a true evolution theory; that it comes in play only as the last term of a series of evolutionary agencies or causes; and that it rather accounts, as first suggested by the Duke of Argyll, for the preservation of forms than for their origination. We may, in fact, compare Darwinism to the apex of a pyramid, the larger mass of the pyramid representing the complex of theories necessary to account for the world of life as it has been and now is. In other words, we believe in a modified and greatly extended Lamarckianism, or what may be called Neo-Lamarckianism."

[227] Studies in the Theory of Descent. By Dr. August Weismann. Translated and edited, with notes, by Raphael Meldola. London, 1882. 2 vols.

[228] "The Influence of Physical Conditions in the Genesis of Species," Radical Review, i., May, 1877. See also J. A. Allen in Bull. Mus. Comp. Zooel. ii., 1871; also R. Ridgway, American Journal of Science, December, 1872, January, 1873.

[229] Annual Report of the United States Geological and Geographical Survey Territories, 1873. Pp. 543-560. See also the author's monograph of Geometrid Moths or Phalaenidae of the United States, 1876, pp. 584-589, and monograph of Bombycine Moths (Notodontidae), p. 50.

[230] Proceedings Academy of Natural Science, Philadelphia (1877), p. 318.

[231] Proceedings of the American Philosophical Society (1889), p. 546.

[232] Transactions American Philosophical Society, xvi. (1890), and later papers.

[233] American Journal of Morphology (1891), pp. 395, 398.

[234] "Ueber die Darwinische Theorie in Besug auf die geographische Verbreitung der Organismen." Sitzenb. der Akad. Muenchen, 1868. Translated by J. L. Laird under the title, The Darwinian Theory and the Law of the Migration of Organisms. London, 1873. Also Ueber den Einfluss der geographischen Isolirung und Colonierbildung auf die morphologischen Veraenderungen der Organismen. Muenchen, 1870.

[235] Linnaean Society's Journal: Zooelogy, xi., 1872.

[236] Linnaean Society's Journal: Zooelogy, xx., 1887, pp. 189-274, 496-505: also Nature, July 18, 1872.

[237] Evolution without Natural Selection; or, The Segregation of Species without the aid of the Darwinian Hypothesis, London (1885), pp. 1-80.

[238] Revue Scientifique, xix. (1877). p. 669. Quoted by Giard in Rev. Sci., 1889, p. 646.

[239] Animal Life as Affected by the Natural Conditions of Existence. By Karl Semper. The International Scientific Series. New York, 1881.

[240] Organic Evolution as the Result of the Inheritance of Acquired Characters, according to the Laws of Organic Growth. Translated by J. T. Cunningham, 1890.

[241] On Orthogenesis and the Impotence of Natural Selection in Species Formation. Chicago, 1898.

[242] Die Farbenevolution bei den Pieriden. Leiden, 1898.

[243] "On Mechanical Selection and Other Problems." Novitates Zoologicae, iii. Tring, 1896.

[244] Entwicklung der Raupenzeichnung und Abhaengigkeit der letzeren von der Farbe der Umgebung, 1894.

[245] Transmutation der Schmetterlinge infolge Temperatur-veraenderungen, 1895.

[246] Ueber den Einfluss der Temperatur bei der Erzeugung der Schmetterlings-varietaeten, 1880.

[247] Ueber Farbenwechsel bei niederen Wirbelthieren, bedingt durch directe Wirkung des Lichts auf die Pigmentzellen. Centralblatt fuer Physiologie, 1891, v., p. 326.

[248] Ueber den Farbenwechsel der Froesche. Pflueger's Archiv fuer Physiologie, 1892, li., p. 455.

[249] Lecon d'Ouverture du Cours de l'Evolution des Etres organises. Paris, 1888, and "Les Facteurs de l'Evolution," Revue Scientifique, November 23, 1889.

[250] Revue Encyclopedique, 1897. p. 325. Yet we have an example of the appearance of a new organ in the case of the duckbill, in which the horny plates take the place of the teeth which Poulton has discovered in the embryo. Other cases are the adductor muscles of shelled crustacea. (See p. 418.)

[251] La Philosophie Zoologique avant Darwin. Paris, 1884, p. 76.

[252] "Lamarckism and Darwinism." Proceedings Boston Society Natural History, xxv., 1890, pp. 42-49.

[253] "The Origin of Species without the Aid of Natural Selection," Natural Science, Oct., 1894. Also, "The Origin of Plant Structures."

[254] "Does Natural Selection play any Part in the Origin of Species among Plants?" Natural Science, Sept., 1897.

[255] "Essay on the Development Hypothesis," 1852, London Times.

[256] "A Theoretical Origin of Endogens from Exogens through Self-Adaptation to an Aquatic Habit," Linnean Society Journal: Botany, 1892, l. c., xxix., pp. 485-528. A case analogous to kinetogenesis in animals is his statement based on mathematical calculations by Mr. Hiern, "that the best form of the margin of floating leaves for resisting the strains due to running water is circular, or at least the several portions of the margin would be circular arcs" (p. 517).

[257] "De l'Influence du Milieu sur la Structure anatomique des Vegetaux," Ann. Sci. Nat. Bot., ser. 6, xii., 1881, p. 167.

[258] "Notes on the Regional Distribution of the Cape Flora," Transactions Botanical Society, Edinburgh. 1891, p. 241.

[259] Les Vegetaux et les Milieux cosmiques, Paris, 1898, pp. 292.

[260] Proceedings Biological Society of Washington, 1890.

[261] "Phylogeny of the Pelecypoda," Memoirs Boston Society Natural History, iv., 1890, pp. 277-400. Also, American Naturalist, 1891, xxv., pp. 11-21.

[262] "Transformations of Planorbis at Steinheim, with Remarks on the Effects of Gravity upon the Forms of Shells and Animals," Proceedings A. A. A. S., xxix., 1880.

[263] Der Kampf der Theile im Organismus. Leipzig, 1881. Also Gesammelte Abhandlungen ueber Entwickelungsmechanik der Organismen. Leipzig, 1895.

[264] Die Unwandlung der Arten ein Vorgang functioneller Selbsgestaltung. Leipzig, 1894.

[265] Gedanken zur Descendenz- und Vererbungstheorie; Biol. Centralblatt, xiii., 1893, 397-420.

[266] Entwickelungmecanische Studien, 1892-93.

[267] Experimental Evolution, 1892; also, "Recherches sur le Nanisme experimental," Journ. Anat. et Phys., 1894.

[268] "Ueber die organsplastischen Kraefte der Organismen," Arbeit. nat. Ges., Petersburg, xvi., 1885; Protok, 79-82.

[269] General Physiology, 1899.

[270] Experimental Morphology, 1897-99. 2 vols.

[271] "Modifications of Certain Organs which seem to be Illustrations of the Inheritance of Acquired Characters in Mammals and Birds." Zool. Jahrb. Syst. Abth., 1890, iv., pp. 629-646; also, The Lost Link, by E. Haeckel, with notes, etc., by H. Gadow, 1899.

[272] Proceedings Biological Society of Washington, vi., 1892, pp. 13, 19.

[273] Lay Sermons, Addresses, and Reviews, 1870, p. 323.




Flore francaise ou description succinte de toutes les plantes qui croissent naturellement en France, disposees selon une nouvelle methode d'analyse et a laquelle on a joint la citation de leurs vertus les moins equivoques en medecine et de leur utilite dans les arts. Paris (Impr. Nationale), 1778. 8vo, 3 vol.

Vol. I. Ext. du Rapport fait par MM. Duhamet et Guettard de cet ouvrage. pp. 1-4.

Discours preliminaire. pp. i-cxix. Principes elementaires de Botanique. pp. 1-223. Methode analytique.—Plantes cryptogames. pp. 1-132, viii, pl.

Vol. II. Methode analytique.—Plantes adultes, ou dont les fleurs sont dans un etat de developpement parfait. pp. iv., 684.

Vol. III. Methode analytique. pp. 654, x.

Idem. 2e edit. Paris, 1793.


Flore francaise ou description succinte de toutes les plantes qui croissent naturellement en France, disposees selon une nouvelle methode d'analyse, et precedees par un expose des principes elementaires de la Botanique.

(En collaboration avec A. P. de Candolle). Edition III. Paris (Agasse), 1805. 4 vol., 8vo.

Vol. I. Lettre de M. de Candolle a M. Lamarck. pp. xv.

Discours preliminaire. (Reimpression de la 1re edit.) pp. 1-60. Principes elementaires de Botanique, pp. 61-224. Methode analytique: {analyse des genres. pp. 1-76. {analyse des especes. pp. 77-388, 10 pl.

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Vol. IV. " " pp. 944.

Meme edition, augmentee du tome 5 et tome 6, contenant 1300 especes non decrites dans les cinq premiers volumes. Paris (Desray), 1815. 8vo, pp. 622.

Lettre de M. A. P. de Candolle a M. Lamarck, pp. 10.


Dictionnaire botanique.—(En Encyclopedie methodique. Paris, in 4to.) I, 1783; II, 1786; pour le IIIe volume, 1789, Lamarck a ete aide par Desrousseaux. Le IVe, 1795, est de Desrousseaux, Poiret et Savigny. Les derniers: V, 1804; VI, 1804; VII, 1806; et VIII, 1808, sont de Poiret.

Lamarck et Poiret. Encyclopedie method.: Botanique. 8 vols. et suppl. 1 a 3, avec 900 pl.


Memoire sur un nouveau genre de plante nomme Brucea, et sur le faux Bresillet d'Amerique. Mem. Acad. des Sci. 21 janvier 1784. pp. 342-347.

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