ge.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 a.s.serted 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 circ.u.mstances 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 pa.s.s 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, p.r.i.c.kly, 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.[1] 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 [1] 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 a.s.sociative quality. But it is rarely attended to; even when the a.s.sociations 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 const.i.tuted a unique and long unsmelled perfume which had sunk deep into my memory. And as I pa.s.sed a room which contained the same elements of odor, all those things that were a.s.sociated with that odor at the time I first smelt it, immediately recurred.
Everybody experiences such a.s.sociations 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 a.s.sociation 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 a.s.sociated 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 pa.s.sionate 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, a.s.safoetida, 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 circ.u.mstances. With regard to s.e.x, the sense of smell, according to Lombroso,[1] 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.
[1] 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 a.s.saults, 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 a.s.sures 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 a.s.sured 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 a.s.serts 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 s.p.a.ce-sense and the pressure-sense being equivalent in both s.e.xes. On these special forms of the touch-sense injections of various kinds have decided influence. The injection of morphine, e. g., reduces the s.p.a.ce-sense in the skin. Cannabinum tannic.u.m 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 p.r.o.nouncements 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,[1] "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.
[1] 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 a.s.serted 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 const.i.tution, but otherwise the time a.s.signed 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 p.r.i.c.k 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 a.s.serted 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 a.s.sertions 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 a.s.serted by couleur-students[1] 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.
[1] 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 a.s.sault, which wound is to be a.s.signed 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. Repet.i.tion, 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 gla.s.s 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,[1] 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.
[1] 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,