A still more remarkable illustration of the effects of use and disuse is seen in the sense of touch in different parts of the body. Prof. Weber, in his laboratory for experimental psychology, has worked out this difference most minutely. He finds that by taking a pair of compasses, the points of which are less than one-twelfth of an inch apart, the end of the forefinger is not able to distinguish more than one point. Going to the middle of the back we have the least discriminating power in the skin, for the points must be separated two and one half inches before the nerves can decide that there are two. Any one may test this on himself. Between these extremes we have many differences. The end of the nose has four times as great power of discrimination as the forehead. When we come to the tip of the tongue, we find it far excels any part of the body in its power of tactual discrimination, it being twice that of the forefinger. In every case we find there is greatest delicacy of touch in those parts where this sense has been most exercised. The tongue is being constantly exercised on our food, on the roof of the mouth, the teeth, etc. It is rarely idle. There is in man no advantage for his survival, Mr. Spencer asserts, by having such a sensitive tongue. He could get on just as well without it. He regards it as a case where the exercise of a function has exalted it remarkably, and this exaltation has been transmitted to offspring. Natural selection, he thinks, is not sufficient to account for it. Natural selection only preserves those characters which will give their possessor some advantage in the struggle for existence. Still another argument is drawn from the whale. This monster once lived, it is believed, partly on land, probably on low land near water, and must have been smaller than now. It had hind legs; but since it has lived continuously in the water its tail has so developed as to make a far better organ of locomotion, and the legs have dwindled from disuse, so that now there is only a remnant left, and this is hidden beneath the skin. The tail has become more efficient from use, and this has been transmitted so that all whales are born with well developed tails. The legs have dwindled for want of use until they have almost disappeared; and this effect of disuse has also been transmitted to offspring. Another illustration is furnished by Havelock Charles, an English surgeon, who has spent much time among the Punjab tribes in India, and studied them anthropologically. His account is given in "The Journal of Anatomy," in a paper on the structure of the skeletons of these people. It appears they have facets on the bones, fitting them for the sitting posture. These do not develop after birth, but are seen in the fetus. It seems hardly possible that these facets could have any other origin except by transmission after being acquired by ages of use of sitting posture.