In addition we often think that the clearness of an object represents its distance and suppose that the first alone determines the latter. But the distinctness of objects, i. e., the perceptibility of a light-impression, depends also upon the absolute brightness and the differences in brightness. The latter is more important than is supposed. Try to determine how far away you can see a key-hole when the wall containing the door is in the shadow, and when there is a window opposite the key-hole. A dark object of the size of a key-hole will not be visible at one hundredth of the distance at which the key-hole is perceived. Moreover, the difference in intensity is not alone in consideration; the intensity of the object *with regard to its background has yet to be considered. Aubert has shown that the accuracy of the distinction is the same when a square of white paper is looked at from an angle of 18'', and when conversely a square of black paper on white background is looked at from an angle of 85''. "When we put a gray paper in the sunshine, it may become objectively brighter than white paper in shadow. But this does not prevent us from knowing one as gray and the other as pure white. We separate the color of the object from the intensity of the incident light.'' But this is not always so simple, inasmuch as we know in the case in hand which paper is gray and which white, which is in the sunlight and which in the shadow. But if these facts are not known mistakes often occur so that a man dressed in dark clothes but in full light will be described as wearing lighter clothes than one who wears light clothes in the shadow.
Differences of illumination reveal a number of phenomena difficult to explain. Fechner calls attention to the appearance of stars: "At night everybody sees the stars, in daylight not even Sirius or Jupiter is seen. Yet the absolute difference between those places in the heavens where the stars are and the environing places is just as great as in the night—there is only an increase in illumination.'' Of still greater importance to us is the circumstance noted but not explained by Bernstein. If, in daylight, we look into a basement room from outside, we can perceive nothing, almost; everything is dark, even the windows appear black. But in the evening, if the room is ever so slightly illuminated, and we look into it from outside, we can see even small articles distinctly. Yet there was much intenser light in the room in question during the day than the single illumination of the night could have provided. Hence, it is asserted, the difference in this case is a standard one. In open day the eye is accustomed to the dominating brightness of daylight, beside which the subdued illumination of the room seems relatively dark. But in the evening one is in the dark, and hence even the little light of a single candle is enough to enable one to see. That this explanation is untrue is shown by the fact that the phenomenon is not regulated even when the circumstances in question are made identical. If, for example, you approach the window in daylight with your eyes shut, lean your forehead against the pane and shut out the light on the sides with your hands, and then open your eyes, you see as little in the room as when you looked into it without performing this ceremony. So again, if during the night you gazed at some near-by gas lamp and then glanced into the room, there is only a few moments' indistinctness at most, after that the single candle is enough. The reason, then, must be different from the assigned one—but whatever it is, we need only to maintain that immediate judgment concerning numerous cases involving situations of this kind would be overhasty. It is often said that a witness was able to see this or that under such and such illumination, or that he was unable to see it, although he denies his ability or inability. The only solution of such contradictions is an experiment. The attempt must be made either by the judge or some reliable third person, to discover whether, under the same conditions of illumination, anything could be seen at the place in question or not.
As to *what may be seen in the distance, experiment again, is the best judge. The human eye is so very different in each man that even the acute examination into what is known of the visual image of the Pleiades shows that the *average visual capacity of classic periods is no different from our own, but still that there was great variety in visual capacity. What enormous visual power is attributed to half-civilized and barbarous peoples, especially Indians, Esquimos, etc.! Likewise among our own people there are hunters, mountain guides, etc., who can see so clearly in the distance that mere stories about it might be fables. In the Bosnian campaign of 1878 we had a soldier who in numerous cases of our great need to know the enemy's position in the distance could distinguish it with greater accuracy than we with our good field-glasses. He was the son of a coal-miner in the Styrian mountains, and rather a fool. Incidentally it may be added that he had an incredible, almost animal power of orientation.
As we know little concerning far-sightedness, so also we are unable to define what near-sighted people can see. Inasmuch as their vision does not carry, they are compelled to make intellectual supplementations. They observe the form, action, and clothes of people more accurately than sharp-eyed persons, and hence recognize acquaintances at a greater distance than the latter. Therefore, before an assertion of a short-sighted man is doubted an experiment should be made, or at least another trustworthy short-sighted person should be asked for his opinion.
The background of objects, their movement and form have decided effects on the difference in visual perception. It is an ancient observation that lengthy objects like poles, wires, etc., are visible at incomparably greater distances than, e. g., squares of the same length. In examination it has been shown that the boundary of accurate perception can hardly be determined. I know a place where under favorable illumination taut, white and very thin telephone wires may be seen at a distance of more than a kilometer. And this demands a very small angle of vision.
Humboldt calls attention to the large number of "optical fables.'' He assures us that it is certainly untrue that the stars may be seen in daylight from a deep well, from mines, or high mountains, although this has been repeatedly affirmed since Aristotle.
The explanation of our power to see very thin, long objects at a very great distance, is not our affair, but is of importance because it serves to explain a number of similar phenomena spoken of by witnesses. We have either incorrectly to deny things we do not understand, or we have to accept a good deal that is deniable. We will start, therefore, with the well-known fact that a point seen for a considerable time may easily disappear from perception. This has been studied by Helmholtz and others, and he has shown how difficult it is to keep a point within the field of vision for only ten or twenty minutes. Aubert examines older studies of the matter and concludes that this disappearance or confusion of an object is peripheral, but that fixation of a small object is always difficult. If we fix a distant point it is disappearing at every instant so that an accurate perception is not possible; if however we fix upon a long, thin body, e. g., a wire, it is unnecessary to fix a single point and we may see the object with a wandering eye, hence more clearly.
Helmholtz adds that weakly objective images disappear like a wet spot on warm tin, at the moment a single point is fixed, as does e. g., a landscape seen at night. This last acute observation is the basis of many a testimony concerning the sudden disappearance of an object at night. It has helped me in many an examination, and always to advantage.
In this connection the over-estimation of the moon's illuminating power is not to be forgotten. According to Helmholtz the power of the full moon is not more than that of a candle twelve feet away. And how much people claim to have seen by moonlight! Dr. Vincent says that a man may be recognized during the first quarter at from two to six meters, at full moon at from seven to ten meters, and at the brightest full moon, an intimate may be recognized at from fifteen to sixteen meters. This is approximately correct and indicates how much moonlight is over-estimated.
 Vincent: Trait de Mdecine lgale de Lgrand du Saule.
In addition to the natural differences of sight there are also those artificially created. How much we may help ourselves by skilful distinctions, we can recognize in the well-known and frequently- mentioned business of reading a confused handwriting. We aim to weaken our sense-perception in favor of our imagination, i. e. so to reduce the clearness of the former as to be able to test upon it in some degree a larger number of images. We hold the MS. away from us, look at it askant, with contracted eyebrows, in different lights, and finally we read it. Again, the converse occurs. If we have seen something with a magnifying glass we later recognize details without its help. Definite conditions may bring to light very great distinctions. A body close to the face or in the middle distance looks different according as one eye or both be used in examining it. This is an old story and explains the queer descriptions we receive of such objects as weapons and the like, which were suddenly held before the face of the deponent. In cases of murderous assault it is certain that most uncanny stories are told, later explained by fear or total confusion or intentional dishonesty, but really to be explained by nothing more than actual optical processes.
I do not believe that binocular vision is of much importance in the law; I know of no case in ordinary vision where it matters whether one or both eyes have been used. It is correct to assert that one side or the other of a vertically held hand will be clearer if, before looking at it with both eyes, you look at it with one or the other, but this makes little difference to our purpose. It must be maintained that a part of what we see is seen with one eye only,—if, e. g., I look at the sky and cover one eye with my hand, a certain portion of the heaven disappears, but I observe no alteration in the remaining portion. When I cover the other eye, other stars disappear. Therefore, in binocular vision certain things are seen with one eye only. This may be of importance when an effect has been observed first with both eyes, then with one; raising the question of the difference in observation—but such a question is rare.
There are two additional things to consider. The first is the problem of the influence of custom on increasing visual power in darkness. This power is as a rule undervalued. No animal, naturally, can see anything in complete darkness. But it is almost unbelievable how much can be seen with a very little light. Here again, prisoners tell numerous stories concerning their vision in subterranean prisons. One saw so well as to be able to throw seven needles about the cell and then to find them again. Another, the naturalist Quatremre- Disjonval, was able so accurately to observe the spiders in his cell as to make the observation the basis for his famous "Aranologie.'' Aubert tells of his having had to stay in a room so dark as to make it necessary for others to feel their way, but nevertheless being able to read books without detection because the others could not see the books.
How quickly we get used to darkness and how much more we see after a while, is well known. It is also certain that the longer you are in darkness the more you see. You see more at the end of a day than after a few hours, and at the end of a year, still more. The eye, perhaps, changes in some degree for just this purpose. But a prolonged use of the visual mechanism tends to hypertrophy— or atrophy, as the eyes of deep-sea fishes show. It is well, in any event, to be careful about contradicting the testimonies of patients who have long lived in the dark, concerning what they have seen. The power to see in the dark is so various that without examination, much injustice may be done. Some people see almost nothing at twilight, others see at night as well as cats. And in court these differences must be established and experimentally verified.
The second important element is the innervation of the muscles in consequence of movement merely seen. So Stricker points out, that the sight of a man carrying a heavy load made him feel tension in the muscles involved, and again, when he saw soldiers exercising, he almost was compelled openly to act as they. In every case the muscular innervation followed the visual stimulus.
This may sound improbable but, nevertheless, everybody to some degree does the identical things. And at law the fact may be of importance in cases of assault and battery. Since I learned it, I have repeatedly observed in such cases, from harmless assault to murder, that people, although they had not been seen to deal any blows, were often accused of complicity simply because they were making suspicious movements that led to the following inference: "They stuck their hands into their trousers pocket looking for a knife, clenched their fists, looked as if they were about to jump, swung their hands.'' In many such cases it appeared that the suspects were harmless spectators who were simply more obvious in their innervation of the muscles involved in the assault they were eagerly witnessing. This fact should be well kept in mind; it may relieve many an innocent.
Section 38. (2) Color Vision.
Concerning color vision only a few facts will be mentioned: 1. It will be worth while, first of all, to consider whether color exists. Liebmann holds that if all the people were blind to red, red would not exist; red, i. e., is some cervical phantasy. So are light, sound, warmth, taste, etc. With other senses we have another world. According to Helmholtz, it is senseless to ask whether cinnabar is red as we see it or is only so as an optical illusion. "The sensation of red is the normal reaction of normally constructed eyes to light reflected from cinnabar. A person blind to red, will see cinnabar as black, or a dark grayish yellow, and this is the correct reaction for these abnormal eyes. But he needs to know that his eyes are different from those of other people. In itself the sensation is neither more correct nor less correct than any other even though those who can see red are in the great majority. The red color of cinnabar exists as such only in so far as there are eyes which are similar to those of the majority of mankind. As such light reflected from cinnabar may not properly be called red; it is red only for especial kinds of eyes.'' This is so unconditionally incorrect that an impartial judge of photography says that everything that normal eyes call violet and blue, is very bright, and everything they call green and red is very dark. The red-blind person will see as equal certain natural reds, greens and gray-yellows, both in intensity and shadow. But on the photograph he will be able to distinguish the differences in brightness caused by these three otherwise identical colors. We may, therefore, assume that colors possess *objective differences, and that these objective differences are perceived even by persons of normal vision. But whether I am able to sense the same effect in red that another senses, and whether I should not call red blue, if I had the color-vision of another, is as impossible to discover as it is useless. When the question of color is raised, therefore, we will try to discover only whether the person in question has normal color- vision, or what the nature and degree of his abnormality may be.
 W. Heinrich: bersicht der Methoden bei Untersuchung der Farbenwahr. nehmungen. Krakau 1900.
2. It is not unimportant to know whether single tints are recognizable in the distance. There have been several examinations of this fact. Aubert constructed double squares of ten millimeters and determined the angle of vision at which the color as such could be seen. His results were:
COLOR OF THE WHITE BLACK SQUARE BACKGROUND White 39'' Red 1' 43'' 59'' Light Green 1' 54'' 1' 49'' Dirty Red 3' 27'' 1' 23'' Blue 5' 43'' 4' 17'' Brown 4' 55'' 1' 23''
Light Blue 2' 17'' 1' 23'' Orange 1' 8'' 0' 39'' Gray 4' 17'' 1' 23'' Rose 2' 18'' 3' 99'' Yellow 3' 27'' 0' 39''
 Physiologie der Netzha.ut. Breslau 1865.
It is interesting to notice that the angle for blue on a white background is almost nine times that for white, orange, or yellow on a black background. In cases where colors are of importance, therefore, it will be necessary to discover the color and the nature of its background before the accuracy of the witness can be established.
3. It is well known that in the diminution of brightnesses red disappears before blue, and that at night, when all colors have disappeared, the blue of heaven is still visible. So if anybody asserts that he has been able to see the blue of a man's coat but not his red-brown trousers, his statement is possibly true, while the converse would be untrue. But there are no reliable or consonant accounts of the order in which colors disappear in increasing darkness. The knowledge of this order would help a great deal in the administration of criminal justice.
4. The retina will not see red at the periphery, because there are no red rods there. A stick of red sealing wax drawn across the eye from right to left, appears at the periphery of the visual field to be black. If, then, a witness has not looked right at a definitely red object, and has seen it askance, he has certainly not observed its color. The experiment may be made by anybody.
5. According to Quantz objects in less refractable colors (red, orange, yellow, and purple) look 0.2 to 3.6% bigger against white, while blue, blue-green, and violet objects appear from 0.2 to 2.2% smaller. Dark and long-lined objects seem longer; bright and horizontal seem wider. And these facts are significant when witnesses judge of size.
 J. O. Quantz: The Influence of the Color of Surfaces on our Estimation of their Magnitudes. Am. Journal of Psychology VII, 95.
6. If colors are observed through small openings, especially through very small holes, the nuances become essentially different and green may even seem colorless.
7. According to Aubert, sparkle consists of the fact that one point in a body is very bright while the brightness diminishes almost absolutely from that point; e. g., a glancing wire has a very narrow bright line with deep shadows on each side; a ball of mercury in a thermometer, a shining point and then deep shadow. When we see this we say it sparkles because we unite it with a number of similar observations. It is therefore conceivable that at a great distance, under conditions of sharp or accidental illuminations, etc., we are likely to see things as sparkling which do not do so in the least. With the concept "sparkling,'' moreover, we tend to unite, at least under certain circumstances, definite images, and hence "glancing weapons'' are often seen in places where there were only quite harmless dull objects. So also coins are seen to sparkle where really there are none.
Section 39. (3) The Blind Spot.
Everybody knows what the blind spot is, and every psychology and physiology text-book talks about it. But as a rule it is identified only with the little point and the tiny cross pictured in the textbooks, and it is supposed that it does not much matter if the little cross, under certain circumstances, can not be seen. But it must not be forgotten that the size of the blind spot increases with the distance so that at a fairly great distance, possibly half the length of a room, the blind spot becomes so great that a man's head may disappear from the field of vision. According to Helmholtz: "The effect of the blind spot is very significant. If we make a little cross on a piece of paper and then a spot the size of a pea two inches to the right, and if we look at the cross with the left eye closed, the spot disappears. The size of the blind spot is large enough to cover in the heavens a plate which has twelve times the diameter of the moon. It may cover a human face at a distance of 6', but we do not observe this because we generally fill out the void. If we see a line in the place in question, we see it unbroken, because we know it to be so, and therefore supply the missing part.''
A number of experiments have been made with more or less success to explain the blind spot. It is enough for us to agree that we see habitually with both eyes and that the "spot as big as a pea'' disappears only when we look at the cross. But when we fix our eyes on anything we pay attention to that only and to nothing else. And it is indifferent to us if an uninteresting object disappears, so that the moment we begin to care about the "spot as large as a pea,'' it is immediately to hand and needs no imaginative completion. If it be objected that fixing with the eyes and being interested are not identical, we reply that a distinction is made only in experiment. You fix one point and are interested in the other because you expect it to disappear. And this experiment, as anybody will immediately recognize, has its peculiar difficulty, because it requires much concentration *not to look at the point which interests us. This never happens in the daily life, and it will not be easy to fix a point which is not interesting.
At the same time there are conceivable cases in which objects seen askance may be of importance, and where the visual fixation of a single point will not reveal every reflection that fell on the blind spot. I have not met with a practical case in which some fact or testimony could be explained only by the blind spot, but such cases are conceivable.
Section 40. (c) The Sense of Hearing.
We have two problems with regard to sound—whether the witnesses have heard correctly, and whether we hear them correctly. Between both witnesses and ourselves there are again other factors. Correct comprehension, faithful memory, the activity of the imagination, the variety of influences, the degree of personal integrity; but most important is the consideration, whether the witness has heard correctly. As a general thing we must deny in most cases completely accurate reproduction of what witnesses have heard. In this connection dealing with questions of honor is instructive. If the question is the recall of slander the terms of it will be as various as the number of witnesses. We discover that the sense, the tendency of slander is not easily mistaken. At least if it is, I have not observed it. The witness, e. g., will confuse the words "scamp,'' "cheat,'' "swindler,'' etc., and again the words: "ox,'' "donkey,'' "numbskull,'' etc. But he will not say that he has heard "scamp'' where what was said was "donkey.'' He simply has observed that A has insulted B with an epithet of moral turpitude or of stupidity and under examination he inserts an appropriate term. Often people hear only according to meanings and hence the difficulty of getting them to reproduce verbally and directly something said by a third person. They always engage upon indirect narration because they have heard only the meaning, not the words. Memory has nothing to do with this matter, for when in examination, a witness is requested to reproduce directly what he has just heard, he will reproduce no more than the sense, not the words. Not to do so requires an unusual degree of intelligence and training.
Now if the witnesses only reproduced the actual meaning of what they heard, no harm would be done, but they tell us only what they *suppose to be the meaning, and hence we get a good many mistakes. It does seem as if uneducated and half-educated people are able to shut their ears to all things they do not understand. Even purely sensory perception is organized according to intelligent capacity.
If this is kept in mind it will be possible correctly to interpret testimonies in those difficult instances in which one man narrates what he has heard from another concerning his own statement, and where it might be quite impossible to judge the nature and culture of this third person. There are a few other conditions to consider besides.
If we have to discover a person's hearing power or his hearing power under definite conditions, it is best never to depend, in even slightly important cases, on vocal tests merely. The examination must be made by experts, and if the case is really subtle it must be made under the same circumstances of place and condition, and with the same people as in the original situation. Otherwise nothing certain can be learned.
The determination of auditory power is, however, insufficient, for this power varies with the degree any individual can distinguish a single definite tone among many, hear it alone, and retain it. And this varies not only with the individual but also with the time, the place, the voice, etc. In my bed-room, e. g., and in three neighboring rooms I have wall-clocks each of which is running. The doors of the room are open right and left. At night when everything is quiet, I can sometimes hear the ticking of each one of these clocks; immediately isolate one completely and listen to that so that the ticking of the other three completely disappears. Then again I may kindly command myself not to hear this ticking, but to hear one of the other three, and I do so, though I fail to hear two clocks together at just the same instant. On another day under similar circumstances I completely fail in this attempt. Either I hear none of the clocks in particular, or only for a short time, which results in the ticking's being again lost in the general noise; or I do hear the ticking of one clock, but never of that which I have chosen to hear.
This incident is variously explicable and the experiment may be repeated with various persons. It indicates that auditory capacity is exceedingly differentiated and that there is no justification for aprioristic doubt of especial powers. It is, however, admittedly difficult to say how experiments can be made under control.
There are still a few more marvels. It is repeatedly asserted, e. g., by Tyndall, that a comparatively large number of people do not hear high tones like the chirping of crickets, although the normal hearing of such people is acute. Others again easily sense deep tones but distinguish them with difficulty because they retain only a roll or roar, but do not hear the individual tones. And generally, almost all people have difficulty in making a correct valuation of the direction of sound. Wundt says that we locate powerful sounds in front of us and are generally better able to judge right and left than before and behind.[1b] These data, which are for us quite important, have been subjected to many tests. Wundt's statement has been confirmed by various experiments which have shown that sound to the right and the left are best distinguished, and sounds in front and below, in front to the right and to the left, and below, to the right and to the left, are least easily distinguished. Among the experimenters were Preyer, Arnheim, Kries, Mnsterberg.
 People of extreme old age do not seem to be able to hear shrill tones. A friend of mine reports this to be the case with the composer, Robert Franz.
[1b] W. Wundt: Grundzge.
All these experiments indicate certain constant tendencies to definite mistakes. Sounds in front are often mistaken for sounds behind and felt to be higher than their natural head-level. Again, it is generally asserted that binaural hearing is of great importance for the recognition of the direction of sound. With one ear this recognition is much more difficult. This may be verified by the fact that we turn our heads here and there as though to compare directions whenever we want to make sure of the direction of sound. In this regard, too, a number of effective experiments have been made.
When it is necessary to determine whether the witness deposes correctly concerning the direction of sound, it is best to get the official physician to find out whether he hears with both ears, and whether he hears equally well with both. It is observed that persons who hear excellently with both ears are unfortunate in judging the direction of sound. Others again are very skilful in this matter, and may possibly get their skill from practice, sense of locality, etc. But in any case, certainty can be obtained only by experimentation.
With regard to the conduction of sound—it is to be noted that sound is carried astonishingly far by means of compact bodies. The distance at which the trotting of horses, the thunder of cannons, etc., may be heard by laying the ear close to the ground is a commonplace in fiction. Therefore, if a witness testifies to have heard something at a great distance in this way, or by having laid his ear to the wall, it is well not to set the evidence aside. Although it will be difficult in such cases to make determinative experiments, it is useful to do so because the limits of his capacity are then approximated.
Under certain circumstances it may be of importance to know what can be heard when the head, or at least the ear, is under water. The experiment may be made in the bath-room, by setting the back of the head under water so that the ears are completely covered but the mouth and the eyes are free. The mouth must be kept closed so that there shall be no intrusion of sound through the Eustachian tube. In this condition practically no sound can be heard which must *first pass through the air. If, therefore, anybody even immediately next to you, speaks ever so loud, you can hear only a minimum of what he says. On the other hand, noises that are conducted by compact bodies, i. e. the walls, the bath, and the water, can be heard with astonishing distinctness, especially if the bath is not detachable but is built into the wall. Then if some remote part of the building, e. g. some wall, is knocked, the noise is heard perfectly well, although somebody standing near the bath hears nothing whatever. This may be of importance in cases of accident, in certain attempts at drowning people, and in accidental eaves-dropping.
There are several things to note with regard to deaf persons, or such as have difficulty with their hearing. According to Fechner, deafness begins with the inability to hear high tones and ends with the inability to hear deep ones, so that it often happens that complainants are not believed because they still hear deep tones. Again, there are mistakes which rise from the fact that the deaf often learn a great deal from the movements of the lips, and the reading of these movements has become the basis of the so-called "audition'' of deaf mutes. There are stories of deaf mutes who have perceived more in this way, and by means of their necessary and well-practised synthesis of impressions, than persons with good hearing power.
The differences that age makes in hearing are of importance. Bezold has examined a large number of human ears of different ages and indicates that after the fiftieth year there is not only a successive decrease in the number of the approximately normal-hearing, but there is a successively growing increase in the degree of auditory limitation which the ear experiences with increasing age. The results are more surprising than is supposed.
Not one of 100 people over fifty years of age could understand conversational speech at a distance of sixteen meters; 10.5% understood it at a distance of eight to sixteen meters. Of school children 46.5% (1918 of them) from seven to eighteen understood it at a distance of 20 meters plus, and 32.7% at a distance of from 16 to 8 meters. The percentage then is 10.5 for people over fifty as against 79.2 of people over seven and under 18. Old women can hear better than old men. At a distance of 4 to 16 meters the proportion of women to men who could hear was 34 to 17. The converse is true of children, for at a distance of 20 meters and more the percentage of boys was 49.9 and girls 43.2. The reason for this inversion of the relation lies in the harmful influences of manual labor and other noisy occupations of men. These comparisons may be of importance when the question is raised as to how much more a witness may have heard than one of a different age.
Section 41. (d) The Sense of Taste.
The sense of taste is rarely of legal importance, but when it does come into importance it is regularly very significant because it involves, in the main, problems of poisoning. The explanation of such cases is rarely easy and certain—first of all, because we can not, without difficulty, get into a position of testing the delicacy and acuteness of any individual sense of taste, where such testing is quite simple with regard to seeing and hearing. At the same time, it is necessary when tests are made, to depend upon general, and rarely constant impressions, since very few people mean the same thing by, stinging, prickly, metallic, and burning tastes, even though the ordinary terms sweet, sour, bitter, and salty, may be accepted as approximately constant. The least that can be done when a taste is defined as good, bad, excellent, or disgusting, is to test it in every possible direction with regard to the age, habits, health, and intelligence of the taster, for all of these exercise great influence on his values. Similarly necessary are valuations like flat, sweetish, contractile, limey, pappy, sandy, which are all dictated by almost momentary variations in well-being.
But if any denotation is to be depended upon, and in the end some one has to be, it is necessary to determine whether the perception has been made with the end or the root of the tongue. Longet, following the experiments of certain others, has brought together definite results in the following table:
TASTE TONGUE-TIP TONGUE ROOT Glauber's salts . . salty bitter Iodkalium . . . . . " " Alum. . . . . . . . sour sweet Glycerine . . . . . none " Rock candy. . . . . " " Chlorate of strychnine " " Natrium carbonate . " alkaloid
 A. Strindberg. Zur Physiologie des Geschmacks. wiener Rundschau, 1900. p. 338 ff.
In such cases too, particularly as diseased conditions and personal idiosyncrasies exercise considerable influences, it will be important to call in the physician. Dehn is led by his experiments to the conclusion that woman's sense of taste is finer than man's, and again that that of the educated man finer than that of the uneducated. In women education makes no difference in this regard.
Section 42. (e) The Sense of Smell.
The sense of smell would be of great importance for legal consideration if it could get the study it deserves. It may be said that many men have more acute olfactory powers than they know, and that they may learn more by means of them than by means of the other senses. The sense of smell has little especial practical importance. It only serves to supply a great many people with occasional disagreeable impressions, and what men fail to find especially necessary they do not easily make use of. The utility of smell would be great because it is accurate, and hence powerful in its associative quality. But it is rarely attended to; even when the associations are awakened they are not ascribed to the sense of smell but are said to be accidental. I offer one example only, of this common fact. When I was a child of less than eight years, I once visited with my parents a priest who was a school-mate of my father's. The day spent in the parsonage contained nothing remarkable, so that all these years I have not even thought of it. A short time ago all the details I encountered on that day occurred to me very vividly, and inasmuch as this sudden memory seemed baseless, I studied carefully the cause of its occurrence, without success. A short time later I had the same experience and at the same place. This was a clew, and I then recalled that I had undertaken a voyage of discovery with the small niece of the parson and had been led into a fruit cellar. There I found great heaps of apples laid on straw, and on the wall a considerable number of the hunting boots of the parson. The mixed odors of apple, straw and boots constituted a unique and long unsmelled perfume which had sunk deep into my memory. And as I passed a room which contained the same elements of odor, all those things that were associated with that odor at the time I first smelt it, immediately recurred.
Everybody experiences such associations in great number, and in examinations a little trouble will bring them up, especially when the question deals with remote events, and a witness tells about some "accidental'' idea of his. If the accident is considered to be an association and studied in the light of a memory of odor, one may often succeed in finding the right clew and making progress.
But accurate as the sense of smell is, it receives as a rule little consideration, and when some question concerning smell is put the answer is generally negative. Yet in no case may a matter be so easily determined as in this one; one may without making even the slightest suggestion, succeed in getting the witness to confess that he had smelled something. Incidentally, one may succeed in awakening such impressions as have not quite crossed the threshold of consciousness, or have been subdued and diverted. Suppose, e. g., that a witness has smelled fire, but inasmuch as he was otherwise engaged was not fully conscious of it or did not quite notice it, or explained it to himself as some kitchen odor or the odor of a bad cigar. Such perceptions are later forgotten, but with proper questioning are faithfully and completely brought to memory.
Obviously much depends on whether anybody likes certain delicate odors or not. As a rule it may be held that a delicate sense of smell is frequently associated with nervousness. Again, people with broad nostrils and well developed foreheads, who keep their mouths closed most of the time, have certainly a delicate sense of smell. People of lymphatic nature, with veiled unclear voices, do not have a keen sense of smell, and still duller is that of snufflers and habitual smokers. Up to a certain degree, practice may do much, but too much of it dulls the sense of smell. Butchers, tobacconists, perfumers, not only fail to perceive the odors which dominate their shops; their sense of smell has been dulled, anyway. On the other hand, those who have to make delicate distinctions by means of their sense, like apothecaries, tea dealers, brewers, wine tasters, etc. achieve great skill. I remember that one time when I had in court to deal almost exclusively with gypsies, I could immediately smell whether any gypsies had been brought there during the night.
Very nervous persons develop a delicateness and acuteness of smell which other persons do not even imagine. Now we have no real knowledge of how odors arise. That they are not the results of the radiation of very tiny parts is shown by the fact that certain bodies smell though they are known not to give off particles. Zinc, for example, and such things as copper, sulphur, and iron, have individual odors; the latter, particularly when it is kept polished by a great deal of friction,—e.g., in the cases of chains, key-rings kept in the pocket.
In defining the impressions of smell great difficulties occur. Even normal individuals often have a passionate love for odors that are either indifferent or disgusting to others (rotten apples, wet sponges, cow-dung, and the odor of a horse-stable, garlic, assafoetida, very ripe game, etc.). The same individual finds the odor of food beautiful when hungry, pleasant when full-fed, and unendurable when he has migraine. It would be necessary to make an accurate description of these differences and all their accompanying circumstances. With regard to sex, the sense of smell, according to Lombroso, is twice as fine in men as in women. This is verified by Lombroso's pupils Ottolenghi and Sicard, Roncoroni and Francis Galton. Experience of daily life does not confirm this, though many smokers among men rarely possess acute sense of smell, and this raises the percentage considerably in favor of women.
 C. Lombroso and G. Ferrero. The Female Offender.
Section 43. (f) The Sense of Touch.
I combine, for the sake of simplicity, the senses of location, pressure, temperature, etc., under the general expression: sense of touch. The problem this sense raises is no light one because many witnesses tell of perceptions made in the dark or when they were otherwise unable to see, and because much is perceived by means of this sense in assaults, wounds, and other contacts. In most cases such witnesses have been unable to regard the touched parts of their bodies, so that we have to depend upon this touch-sense alone. Full certainty is possible only when sight and touch have worked together and rectified one another. It has been shown that the conception of the third dimension can not be obtained through the sense of sight. At the beginning we owe the perception of this dimension only to touch and later on to experience and habit. The truth of this statement is confirmed by the reports of persons who, born blind, have gained sight. Some were unable to distinguish by means of mere sight a silver pencil-holder from a large key. They could only tell them to be different things, and recognized their nature only after they had felt them. On the other hand, the deceptive possibilities in touch are seen in the well-known mistakes to which one is subjected in blind touching. At the same time practice leads to considerable accuracy in touch and on many occasions the sense is trusted more than sight—e. g., whenever we test the delicacy of an object with our finger-tips. The fineness of paper, leather, the smoothness of a surface, the presence of points, are always tested with the fingers. So that if a witness assures us that this or that was very smooth, or that this surface was very raw, we must regularly ask him whether he had tested the quality by touching it with his fingers, and we are certain only if he says yes. Whoever has to depend much on the sense of touch increases its field of perception, as we know from the delicacy of the sense in blind people. The statements of the blind concerning their contact sensations may be believed even when they seem improbable; there are blind persons who may feel the very color of fabrics, because the various pigments and their medium give a different surface- quality to the cloth they color.
In another direction, again, it is the deaf who have especial power. So, we are assured by Abercrombie that in his medical practice he had frequently observed how deaf people will perceive the roll of an approaching wagon, or the approach of a person, long before people with good hearing do so. For a long time I owned an Angora which, like all Angoras, was completely deaf, and her deafness had been tested by physicians. Nevertheless, if the animal was dozing somewhere and anybody came near it, she would immediately notice his steps, and would distinguish them, for she would jump up frightened, if the newcomer was unknown, and would stretch herself with pleasure in the expectation of petting if she felt a friend coming. She would sense the lightest touch on the object she occupied, bench, window-seat, sofa, etc., and she was especially sensitive to very light scratching of the object. Such sensitivity is duplicated frequently in persons who are hard of hearing, and whom, therefore, we are likely to doubt.
The sense of touch is, moreover, improved not only by practice, but also by the training of the muscles. Stricker asserts that he has frequently noticed that the observational capacity of individuals who make much use of their muscles is greater than among persons whose habits are sedentary. This does not contradict the truth established by many experiments that the educated man is more sensitive in all directions than the uneducated. Again, women have a better developed sense of touch than men, the space-sense and the pressure-sense being equivalent in both sexes. On these special forms of the touch-sense injections of various kinds have decided influence. The injection of morphine, e. g., reduces the space-sense in the skin. Cannabinum tannicum reduces sensibility and alcohol is swift and considerable in its effects. According to Reichenbach some sensitives are extreme in their feeling. The best of them notice immediately the approach and relative position of people, or the presence of another in a dark room. That very nervous people frequently feel air pressure, fine vibrations, etc., is perfectly true. And this and other facts show the great variety of touch impressions that may be distinguished. The sense of temperature has a comparatively high development, and more so in women than in men. At the lips and with the tips of the fingers, differences of two-tenths of a degree are perceived. But where an absolute valuation and not a difference is to be perceived, the mean variation, generally, is not much less than 4 degrees. E. g., a temperature of 19 degrees R. will be estimated at from 17 to 21 degrees. I believe, however, that the estimation of very common temperatures must be accepted as correct. E. g., anybody accustomed to have his room in winter 14 degrees R. will immediately notice, and correctly estimate, the rise or fall of one degree. Again, anybody who takes cold baths in summer will observe a change of one degree in temperature. It will, therefore, be possible to believe the pronouncements of witnesses concerning a narrow range of temperatures, but all the conditions of perception must be noted for the differences are extreme. It has been shown, e. g., that the whole hand finds water of 29 degrees R. warmer than water of 32 degrees R. which is merely tested with the finger. Further, Weber points out, "If we put two adjacent fingers into two different warm fluids the sensations flow together in such a way that it is difficult to distinguish differences. But if we use two hands in this test, it is especially successful when we change the hands from one fluid to another. The closer the points on the skin which receive contemporary impressions and perhaps, the closer the portions of the brain to which these impressions are sent, the more easily these sensations flow together while again, the further they are from one another the less frequently does this occur.'' In the practice of criminal law such matters will rarely arise, but estimations of temperature are frequently required and their reliability must be established.
 E. H. Weber: Die Lehre vom Tastsinn u. Gemeingefhl. Braunschweig 1851.
It is important to know what a wounded man and his enemy feel in the first instant of the crime and in what degree their testimonies are reliable. First of all, we have to thank the excellent observations of Weber, for the knowledge that we find it very difficult to discover with closed eyes the angle made by a dagger thrust against the body. It is equally difficult to determine the direction from which a push or blow has come. On the other hand we can tell very accurately in what direction a handful of hair is pulled.
With regard to the time it takes to feel contact and pain, it is asserted that a short powerful blow on a corn is felt immediately, but the pain of it one to two seconds later. It may be that corns have an especial constitution, but otherwise the time assigned before feeling pain is far too long. Helmholtz made 1850 measurements which proved that the nervous current moves 90 feet a second. If, then, you prick your finger, you feel it a thirtieth of a second later. The easiest experiments which may be made in that regard are insufficient to establish anything definite. We can only say that the perception of a peripheral pain occurs an observable period after the shock, i. e., about a third of a second later than its cause.
The sensation of a stab is often identified as contact with a hot object, and it is further asserted that the wounded person feels close to the pain which accompanies the push or the cut, the cold of the blade and its presence in the depths of his body. So far as I have been able to learn from wounded people, these assertions are not confirmed. Setting aside individuals who exaggerate intentionally and want to make themselves interesting or to indicate considerable damage, all answers point to the fact that stabs, shots, and blows are sensed as pushes. In addition, the rising of the blood is felt almost immediately, but nothing else; pain comes much later. It is asserted by couleur-students who have occasion to have a considerable number of duels behind them, that "sitting thrusts,'' even when they are made with the sharpest swords, are sensed only as painless, or almost painless, blows or pushes. Curiously enough all say that the sensation is felt as if caused by some very broad dull tool: a falling shingle, perhaps. But not one has felt the cold of the entering blade.
 Students who are members of student societies distinguished by particular colors.
Soldiers whose shot wounds were inquired into, often just a few minutes after their being wounded, have said unanimously that they had felt only a hard push.
It is quite different with the man who causes the wound. Lotze has rightly called attention to the fact that in mounting a ladder with elastic rungs one perceives clearly the points at which the rungs are fastened to the sides. The points at which an elastic trellis is fastened is felt when it is shaken, and the resistance of the wood when an axe is used on it. In the same way the soldier senses clearly the entrance of his sword-point or blade into the body of his enemy. The last fact is confirmed by the students. One can clearly distinguish whether the sword has merely beaten through the skin or has sunk deeply and reached the bone. And this sensation of touch is concentrated in the *right thumb, which is barely under the hilt of the sword at the point where the grip rests.
The importance of the fact that the wounder feels his success lies in the possibility it gives him, when he wants to tell the truth, to indicate reliably whether and how far he has wounded his opponent. The importance of the testimony of the wounded man lies in its influence on determining, in cases where there were more than one concerned in the assault, which wound is to be assigned to which man. We often hear from the victim who really desires to tell the truth, "I was quite convinced that X dealt me the deep stab in the shoulder, but he has only pushed and not stabbed me— I did not perceive a stab.'' Just the same, it was X who stabbed him, and if the examining judge explains the matter to the victim, his testimony will be yet more honest.
There are still a few other significant facts.
1. It is well known that the portion of the skin which covers a bone and which is then so pulled away that it covers a fleshy part, can not easily identify the point of stimulation. Such transpositions may be made intentionally in this experiment, but they occur frequently through vigorous twists of the body. When the upper part of the body is drawn backwards, while one is sitting down, a collection of such transpositions occur and it is very hard then to localize a blow or stab. So, too, when an arm is held backward in such a way as to turn the flat of the hand uppermost. It is still more difficult to locate a wound when one part of the body is held by another person and the skin pulled aside.
2. The sensation of wetness is composed of that of cold and easy movement over surface. Hence, when we touch without warning a cold smooth piece of metal, we think that we are touching something wet. But the converse is true for we believe that we are touching something cold and smooth when it is only wet. Hence the numerous mistakes about bleeding after wounds. The wounded man or his companions believe that they have felt blood when they have only felt some smooth metal, or they have really felt blood and have taken it for something smooth and cold. Mistakes about whether there was blood or not have led to frequent confusion.
3. Repetition, and hence summation, intensifies and clarifies the sensation of touch. As a consequence, whenever we want to test anything by touching it we do so repeatedly, drawing the finger up and down and holding the object between the fingers; for the same reason we repeatedly feel objects with pleasant exteriors. We like to move our hands up and down smooth or soft furry surfaces, in order to sense them more clearly, or to make the sensation different because of its duration and continuance. Hence it is important, every time something has to be determined through touch, to ask whether the touch occurred once only or was repeated. The relation is not the same in this case as between a hasty glance and accurate survey, for in touching, essential differences may appear.
4. It is very difficult to determine merely by touch whether a thing is straight or crooked, flat, convex or concave. Weber has shown that a glass plate drawn before the finger in such wise as to be held weakly at first, then more powerfully, then again more powerfully seems to be convex and when the reverse is done, concave. Flatness is given when the distance is kept constant.
5. According to Vierordt, the motion of a point at a constant rate over a sizable piece of skin, e. g., the back of the hand from the wrist to the finger tips, gives, if not looked at, the definite impression of increasing rapidity. In the opposite direction, the definiteness is less but increases with the extent of skin covered. This indicates that mistakes may be made in such wounds as cuts, scratches, etc.
 K. Vierordt: Der Zeitsinn nach Versuchen. Tbingen 1868.
6. The problem may arise of the reliability of impressions of habitual pressure. Weber made the earliest experiments, later verified by Fechner, showing that the sensation of weight differs a great deal on different portions of the skin. The most sensitive are the forehead, the temples, the eyelids, the inside of the forearm. The most insensitive are the lips, the trunk and the finger-nails. If piles of six silver dollars are laid on various parts of the body, and then removed, one at a time, the differences are variously felt. In order to notice a removal the following number must be taken away:
One dollar from the top of the finger,
One dollar from the sole of the foot,
Two dollars from the flat of the hand,
Two dollars from the shoulder blade,
Three dollars from the heel,
Four dollars from the back of the head,
Four dollars from the breast,
Five dollars from the middle of the back,
Five dollars from the abdomen.
Further examinations have revealed nothing new. Successful experiments to determine differences between men and women, educated and uneducated, in the acuteness of the sense of pressure, have not been made. The facts they involve may be of use in cases of assault, choking, etc.
Topic 2. PERCEPTION AND CONCEPTION.
What lawyers have to consider in the transition from purely sensory impressions to intellectual conceptions of these impressions, is the possibility of later reproducing any observed object or event. Many so-called scientific distinctions have, under the impulse of scientific psychology, lost their status. Modern psychology does not see sharply-drawn boundaries between perception and memory, and suggests that the proper solution of the problem of perception is the solution of the problem of knowledge.
 The first paragraph, pp. 78-79, is omitted in the translation.
With regard to the relation of consciousness to perception we will make the distinctions made by Fischer. There are two spheres or regions of consciousness: the region of sensation, and of external perception. The former involves the inner structure of the organism, the latter passes from the organism into the objective world. Consciousness has a sphere of action in which it deals with the external world by means of the motor nerves and muscles, and a sphere of perception which is the business of the senses.
 E. L. Fischer: Theorie der Gesichtswahrnehmung. Mainz 1891.
External perception involves three principal functions: apprehension, differentiation, and combination. Perception in the narrower sense of the term is the simple sensory conscious apprehension of some present object stimulating our eyes. We discover by means of it what the object is, its relation to ourselves and other things, its distance from us, its name, etc.
What succeeds this apprehension is the most important thing for us lawyers, i. e. *recognition. Recognition indicates only that an object has sufficiently impressed a mind to keep it known and identifiable. It is indifferent what the nature of the recognized object is. According to Hume the object may be an enduring thing ("non- interrupted and non-dependent on mind''), or it may be identical with perception itself. In the latter case the perception is considered as a logical judgment like the judgment: "It is raining,'' or the feeling that "it is raining,'' and there recognition is only the recognition of a perception. Now judgments of this sort are what we get from witnesses, and what we have to examine and evaluate. This must be done from two points of view. First, from the point of view of the observer and collector of instances who is seeking to discover the principle which governs them. If this is not done the deductions that we make are at least unreliable, and in most cases, false. As Mach says, "If once observation has determined all the facts of any natural science, a new period begins for that science, the period of deduction.'' But how often do we lawyers distinguish these two periods in our own work.
 A sentence is here omitted.
The second point of importance is the presence of mistakes in the observations. The essential mistakes are classified by Schiel under two headings. Mistakes in observation are positive or negative, wrong observation or oversight. The latter occurs largely through preconceived opinions. The opponents of Copernicus concluded that the earth did not move because otherwise a stone dropped from the top of a tower would reach the ground a little to the west. If the adherents of Copernicus had made the experiment they would have discovered that the stone does fall as the theory requires. Similar oversights occur in the lawyer's work hundreds of times. We are impressed with exceptions that are made by others or by ourselves, and give up some already tried approach without actually testing the truth of the exception which challenges it. I have frequently, while at work, thought of the story of some one of the Georges, who did not like scholars and set the following problem to a number of philosophers and physicists: "When I put a ten pound stone into a hundred pound barrel of water the whole weighs a hundred and ten pounds, but when I put a live fish of ten pounds into the barrel the whole still weighs only a hundred pounds?'' Each one of the scholars had his own convincing explanation, until finally the king asked one of the foot-men, who said that he would like to see the experiment tried before he made up his mind. I remember a case in which a peasant was accused of having committed arson for the sake of the insurance. He asserted that he had gone into a room with a candle and that a long spider's web which was hanging down had caught fire from it accidentally and had inflamed the straw which hung from the roof. So the catastrophe had occurred. Only in the second examination did it occur to anybody to ask whether spider's web can burn at all, and the first experiment showed that that was impossible.
Most experiences of this kind indicate that in recognizing events we must proceed slowly, without leaping, and that we may construct our notions only on the basis of knowledge we already possess. Saint Thomas says, "Omnes cognitio fit secundum similitudinem cogniti in cognoscente.'' If this bit of wisdom were kept in mind in the examination of witnesses it would be an easier and simpler task than usual. Only when the unknown is connected with the known is it possible to understand the former. If it is not done the witness will hardly be able to answer. He nowhere finds support, or he seeks one of his own, and naturally finds the wrong one. So the information that an ordinary traveler brings home is mainly identical with what he carries away, for he has ears and eyes only for what he expects to see. For how long a time did the negro believe that disease pales the coral that he wears? Yet if he had only watched it he would have seen how foolish the notion was. How long, since Adam Smith, did people believe that extravagance helps industry, and how much longer have people called Copernicus a fool because they actually saw the sun rise and set. So J. S. Mill puts his opinions on this matter. Benneke adds, "If anybody describes to me an animal, a region, a work of art, or narrates an event, etc., I get no notion through the words I hear of the appearance of the subject. I merely have a problem set me by means of the words and signs, in the conception of the subject, and hence it depends for truth mainly upon the completeness of earlier conceptions of similar things or events, and upon the material I have imaginatively at hand. These are my perceptual capital and my power of representation.''
 E. Benneke: Pragmatische Psychologie.
It naturally is not necessary to ask whether a narrator has ever seen the things he speaks of, nor to convince oneself in examination that the person in question knows accurately what he is talking about. At the same time, the examiner ought to be clear on the matter and know what attitude to take if he is going to deal intelligibly with the other. I might say that all of us, educated and uneducated, have apprehended and remember definite and distinct images of all things we have seen, heard, or learned from descriptions. When we get new information we simply attach the new image to the old, or extinguish a part of the old and put the new in its place, or we retain only a more or less vigorous breath of the old with the new. Such images go far back; even animals possess them. One day my small son came with his exciting information that his guinea pig, well known as a stupid beast, could count. He tried to prove this by removing the six young from their mother and hiding them so that she could not see what happened to them. Then he took one of the six, hid it, and brought the remaining five back to the old lady. She smelled them one after the other and then showed a good deal of excitement, as if she missed something. Then she was again removed and the sixth pig brought back; when she was restored to her brood, she sniffed all six and showed a great deal of satisfaction. "She could count at least six.'' Naturally the beast had only a fixed collective image of her brood, and as one was missing the image was disturbed and incorrect. At the same time, the image was such as is created by the combination of events or circumstances. It is not far from the images of low-browed humanity and differs only in degree from those of civilized people.
The fact that a good deal of what is said is incorrect and yet not consciously untrue, depends upon the existence of these images and their association with the new material. The speaker and the auditor have different sets of images; the first relates the new material differently from a second, and so of course they can not agree. It is the difficult task of the examiner so to adapt what is said as to make it appropriate to the right images without making it possible for incorrect interpretations to enter. When we have a well-known money-lender as witness concerning some unspeakable deal, a street-walker concerning some brawling in a peasant saloon, a clubman concerning a duel, a game-warden concerning poaching, the set of images of each one of these persons will be a bad foundation for new perceptions. On the other hand, it will not be difficult to abstract from them correctly. But cases of this sort are not of constant occurrence and the great trouble consists in once for all discovering what memory-images were present before the witness perceived the event in question. The former have a great influence upon the perception of the latter.
 Cf. H. Gross's Archiv, XV, 125.
In this connection it should not be forgotten that the retention of these images is somewhat pedantic and depends upon unimportant things. In the city hall of Graz there is a secretary with thirty-six sections for the thirty-six different papers. The name of the appropriate journal was written clearly over each section and in spite of the clearness of the script the depositing and removing of the papers required certain effort, inasmuch as the script had to be read and could not be apprehended. Later the name of the paper was cut out of each and pasted on the secretary instead of the script, and then, in spite of the various curly and twisted letters, the habitual images of the titles were easily apprehended and their removal and return became mechanical. The customary and identical things are so habitual that they are apprehended with greater ease than more distinct objects.
Inasmuch as we can conceive only on the basis of the constancy and similarity of forms, we make these forms the essence of experience. On the other hand, what is constant and similar for one individual is not so for another, and essences of experience vary with the experiencer.
"When we behold a die of which we can see three sides at a time, seven corners, and nine edges, we immediately induce the image or schema of a die, and we make our further sense-perception accord with this schema. In this way we get a series of schemes which we may substitute for one another'' (Aubert). For the same reason we associate in description things unknown to the auditor, which we presuppose in him, and hence we can make him rightly understand only if we have named some appropriate object in comparison. Conversely, we have to remember that everybody takes his comparison from his own experience, so that we must have had a like experience if we are to know what is compared. It is disastrous to neglect the private nature of this experience. Whoever has much to do with peasants, who like to make use of powerful comparisons, must first comprehend their essential life, if he is to understand how to reduce their comparisons to correct meanings. And if he has done so he will find such comparisons and images the most distinct and the most intelligible.
Sense-perception has a great deal to do in apprehension and no one can determine the boundary where the sense activity ends and the intellectual begins. I do not recall who has made note of the interesting fact that not one of twenty students in an Egyptian museum knew why the hands of the figures of Egyptian was pictures gave the impression of being incorrect—nobody had observed the fact that all the figures had two right hands.
I once paid a great deal of attention to card-sharping tricks and as I acquired them, either of myself or from practiced gamblers, I demonstrated them to the young criminalists. For a long time I refused to believe what an old Greek told me: "The more foolish and obvious a trick is, the more certain it is; people never see anything.'' The man was right. When I told my pupils expressly, "Now I am cheating,'' I was able to make with safety a false coup, a false deal, etc. Nobody saw it. If only one has half a notion of directing the eyes to some other thing, a card may be laid on the lap, thrust into the sleeve, taken from the pocket, and God knows what else. Now who can say in such a case whether the sensory glance or the intellectual apprehension was unskilful or unpractised? According to some authorities the chief source of error is the senses, but whether something must not be attributed to that mysterious, inexplicable moment in which sensory perception becomes intellectual perception, nobody can say.
My favorite demonstration of how surprisingly little people perceive is quite simple. I set a tray with a bottle of water and several glasses on the table, call express attention to what is about to occur, and pour a little water from the bottle into the glass. Then the stuff is taken away and the astonishing question asked what have I done? All the spectators reply immediately: you have poured water into a glass. Then I ask further with what hand did I do it? How many glasses were there? Where was the glass into which I poured the water? How much did I pour? How much water was there in the glass? Did I really pour or just pretend to? How full was the bottle? Was it certainly water and not, perhaps, wine? Was it not red wine? What did I do with my hand after pouring the water? How did I look when I did it? Did you not really see that I shut my eyes? Did you not really see that I stuck my tongue out? Was I pouring the water while I did it? Or before, or after? Did I wear a ring on my hand? Was my cuff visible? What was the position of my fingers while I held the glass? These questions may be multiplied. And it is as astonishing as amusing to see how little correctness there is in the answers, and how people quarrel about the answers, and what extraordinary things they say. Yet what do we require of witnesses who have to describe much more complicated matters to which their attention had not been previously called, and who have to make their answers, not immediately, but much later; and who, moreover, may, in the presence of the fact, have been overcome by fear, astonishment, terror, etc.! I find that probing even comparatively trained wit- nesses is rather too funny, and the conclusions drawn from what is so learned are rather too conscienceless. Such introductions as: "But you will know,''—"Just recall this one,''—"You wouldn't be so stupid as not to have observed whether,''—"But my dear woman, you have eyes,''—and whatever else may be offered in this kindly fashion, may bring out an answer, but what real worth can such an answer have?
 Cf. Borst u. Claparde: Sur divers Caractres du Temoigna e. Archives des Sciences Phys. et Nat. XVII. Diehl: zum Studium der Merktahugkeit. Beitr. zur Psych. der Aussage, II, 1903
One bright day I came home from court and saw a man step out of a cornfield, remain a few instants in my field of vision, and then disappear. I felt at once that the man had done something suspicious, and immediately asked myself how he looked. I found I knew nothing of his clothes, his dress, his beard, his size, in a word, nothing at all about him. But how I would have punished a witness who should have known just as little. We shall have, in the course of this examination, frequently to mention the fact that we do not see an event in spite of its being in the field of perception. I want at this point merely to call attention to a single well-known case, recorded by Hofmann. At a trial a circumstantial and accurate attempt was made to discover whether it was a significant alteration to bite a man's ear off. The court, the physician, the witnesses, etc., dealt with the question of altering, until finally the wounded man himself showed what was meant, because his other ear had been bitten off many years before,—but then nobody had noticed that mutilated ear.
 Gericht. Medizin. Vienna 1898. p. 447.
In order to know what another person has seen and apprehended we must first of all know how he thinks, and that is impossible. We frequently say of another that he must have thought this or that, or have hit upon such and such ideas, but what the events in another brain may be we can never observe. As Bois-Reymond says somewhere: "If Laplace's ghost could build a homunculus according to the Leibnitzian theory, atom by atom and molecule by molecule, he might succeed in making it think, but not in knowing how it thinks.'' But if we know, at least approximately, the kind of mental process of a person who is as close as possible to us in sex, age, culture, position, experience, etc., we lose this knowledge with every step that leads to differences. We know well what great influence is exercised by the multiplicity of talents, superpositions, knowledge, and apprehensions. When we consider the qualities of things, we discover that we never apprehend them abstractly, but always concretely. We do not see color but the colored object; we do not see warmth, but something warm; not hardness, but something hard. The concept warm, as such, can not be thought of by anybody, and at the mention of the word each will think of some particular warm object; one, of his oven at home; another, of a warm day in Italy; another of a piece of hot iron which burnt him once. Then the individual does not pay constant court to the same object. To-day he has in mind this concrete thing, to-morrow, he uses different names and makes different associations. But every concrete object I think of has considerable effect on the new apprehension; and my auditor does not know, perhaps even I myself do not, what concrete object I have already in mind. And although Berkeley has already shown that color can not be thought of without space or space without color, the task of determining the concrete object to which the witness attaches the qualities he speaks of, will still be overlooked hundreds of times.
It is further of importance that everybody has learned to know the object he speaks about through repetition, that different relations have shown him the matter in different ways. If an object has impressed itself upon us, once pleasurably and once unpleasantly, we can not derive the history and character of the present impression from the object alone, nor can we find it merely in the synthetic memory sensations which are due to the traces of the former coalescing impressions. We are frequently unable, because of this coalescing of earlier impressions, to keep them apart and to study their effect on present impressions. Frequently we do not even at all know why this or that impression is so vivid. But if we are ignorant with regard to what occurs in ourselves, how much can we know about others?
Exner calls attention to the fact that it is in this direction especially, that the "dark perceptions'' play a great rle. "A great part of our intelligence depends on the ability of these 'dark perceptions' to rise without requiring further attention, into the field of consciousness. There are people, e. g., who recognize birds in their flight without knowing clearly what the characteristic flight for any definite bird may be. Others, still more intelligent, know at what intervals the flyers beat their wings, for they can imitate them with their hands. And when the intelligence is still greater, it makes possible a correct description in words.''
Suppose that in some important criminal case several people, of different degrees of education and intelligence, have made observations. We suppose that they all want to tell the truth, and we also suppose that they have observed and apprehended their objects correctly. Their testimonies, nevertheless, will be very different. With the degree of intelligence rises the degree of effect of the "dark subconscious perceptions.'' They give more definite presentation and explanation of the testimony; they turn bare assertions into well-ordered perceptions and real representations. But we generally make the mistake of ascribing the variety of evidence to varying views, or to dishonesty.
To establish the unanimity of such various data, or to find out whether they have such unanimity, is not easy. The most comfortable procedure is to compare the lesser testimonies with those of the most intelligent of the witnesses. As a rule, anybody who has a subconscious perception of the object will be glad to bring it out if he is helped by some form of expression, but the danger of suggestion is here so great that this assistance must be given only in the rarest of cases. The best thing is to help the witness to his full evidence gradually, at the same time taking care not to suggest oneself and thus to cause agreement of several testimonies which were really different but only appeared to look contradictory on account of the effect of subconscious perceptions. The very best thing is to take the testimony as it comes, without alteration, and later on, when there is a great deal of material and the matter has grown clearer, to test the stuff carefully and to see whether the less intelligent persons gave different testimonies through lack of capacity in expression, or because they really had perceived different things and had different things to say.
This is important when the witnesses examined are experts in the matter in which they are examined. I am convinced that the belief that such people must be the best witnesses, is false, at least as a generalization. Benneke (loco cit.), has also made similar observations. "The chemist who perceives a chemical process, the connoisseur a picture, the musician a symphony, perceive them with more vigorous attention than the layman, but the actual attention may be greater with the latter.'' For our own affair, it is enough to know that the judgment of the expert will naturally be better than that of the layman; his apprehension, however, is as a rule one-sided, not so far-reaching and less uncolored. It is natural that every expert, especially when he takes his work seriously, should find most interest in that side of an event with which his profession deals. Oversight of legally important matters is, therefore, almost inevitable. I remember how an eager young doctor was once witness of an assault with intent to kill. He had seen how in an inn the criminal had for some time threatened his victim with a heavy porcelain match-tray. "The os parietale may here be broken,'' the doctor thought, and while he was thinking of the surgical consequences of such a blow, the thing was done and the doctor had not seen how the blow was delivered, whether a knife had been drawn by the victim, etc. Similarly, during an examination concerning breaking open the drawer of a table, the worst witness was the cabinet-maker. The latter was so much interested in the foreign manner in which the portions of the drawer had been cemented and in the curious wood, that he had nothing to say about the legally important question of how the break was made, what the impression of the damaging tool was, etc. Most of us have had such experiences with expert witnesses, and most of us have also observed that they often give false evidence because they treat the event in terms of their own interest and are convinced that things must happen according to the principles of their trades. However the event shapes itself, they model it and alter it so much that it finally implies their own apprehension.
"Subconscious perceptions,'' somewhat altered, play another rle, according to Exner, in so-called orientation. If anybody is able to orient himself, i. e., know where he is at any time and keep in mind the general direction, it is important to be aware of the fact when he serves as witness, for his information will, in consequence, take a different form and assume a different value. Exner says of himself, that he knows at each moment of his climb of the Marcus' tower in what direction he goes. As for me, once I have turned around, I am lost. Our perceptions of location and their value would be very different if we had to testify concerning relations of places, in court. But hardly anybody will assure the court that in general he orients himself well or ill.
As Exner says, "If, when walking, I suddenly stop in front of a house to look at it, I am definitely in possession, also, of the feeling of its distance from where I left the road—the unconscious perception of the road beyond is here at work.'' It might, indeed, be compared with pure subconsciousness in which series of processes occur without our knowing it.
But local orientation does not end with the feeling for place. It is at work even in the cases of small memories of location, e. g., in learning things by heart, in knowing on what page and on what line anything is printed, in finding unobserved things, etc. These questions of perception-orientation are important, for there are people all of whose perceptions are closely related to their sense of location. Much may be learned from such people by use of this specialty of theirs, while oversight thereof may render them hopeless as witnesses. How far this goes with some people—as a rule people with a sense of location are the more intelligent—I saw some time ago when the Germanist Bernhardt Seuffert told me that when he did not know how anything is spelled he imagined its appearance, and when that did not help he wrote both the forms between which he was vacillating and then knew which one was the correct one. When I asked him whether the chirographic image appeared printed or written and in what type, he replied significantly enough, "As my writing-teacher wrote it.'' He definitely localized the image on his writing book of many years ago and read it off in his mind. Such specialties must be remembered in examining witnesses.
In conclusion, there is a word to say concerning Cattell's investigations of the time required for apprehension. The better a man knows the language the more rapidly can he repeat and read its words. It is for this reason that we believe that foreigners speak more rapidly than we. Cattell finds this so indubitable, that he wants to use speed as a test in the examinations in foreign languages.
 J. M. Cattell: ber die Zeit der Erkennung u. Benemlung von Schrift etc. (in Wundt's: Philosophischen Studien II, 1883).
The time used in order to identify a single letter is a quarter of a second, the time to pronounce it one-tenth of a second. Colors and pictures require noticeably more, not because they are not recognized, but because it is necessary to think what the right name is. We are much more accustomed to reading words.