1. Table I. shows that the structures known as touch corpuscles are distributed on those parts of the skin where the stimuli of touch fall most and in propor­tion to the degree in which those parts are employed in tactile discrimina­tion; thus, most of all on the index finger (with the exception of the tip of the tongue) next on the thumb and less on the middle finger. There are 530 of these corpuscles to the upper and 317 to the lower extremity.

2. Table II. bears out the same conclusion, the average number of corpuscles to a square millimetre being twenty-one on the terminal, eight on the second and four on the first phalanges of the index finger, whereas on the foot there are seven on the great toe much exposed to stimuli and only two on the middle of the sole of the foot, which is little exposed. The absence of them from the cornea and conjunctiva, protected by quick and powerful reflexes from such stimuli, and from the (normally) covered glans penis is in accordance with the other results.

3. Table III. dealing with touch spots, shows that these are nearly twice as numerous on the flexor as the dorsal surface of the forearm; and nearly five times as numerous as on the scalp, where tactile stimuli are few, and that the distal phalanx of a finger contains about seven times as many as an area between the shoulders. The regions poor in touch spots are shown to be those where relatively few tactile stimuli can fall.

4. Table IV. gives cold and warmth sensations graded according to the delicacy with which they are perceived in many regions of the skin. The cold sensations are best distinguished on the parts normally most exposed to cold, as the tips of fingers, malleoli, tip of nose, chin, patella, wrist, and least on the protected areas, inner side of thigh, flank, loins and abdomen. The warmth sensations are best distinguished on the regions on which the stimuli of warmth has most frequently fallen, tips of fingers and toes, cavity of mouth, palm of hand, less so on the neck and loin. And the striking fact is noted that warmth sensations are not felt in the lower gums, the inside of the cheek at a certain level and the cornea, which again is protected from these stimuli by its efficient reflex, whereas to the gums and inside of the cheek most warmth stimuli have not been “stimuli” at all.

5. Table V. also gives results of the mode of distribu­tion of cold and warmth spots, examined with punctiform stimuli. The “local sign” for cold is higher than that for warmth spots, and two of these are distinguished as double when only 0.8 millimetres apart on the palm, cheek, chin and forehead, whereas on the upper arm, back and thigh, they are only distinguished as double when separated by two millimetres, and this distance is the minimum at which warmth spots are distinguished as two, that is 2 mm. on the palm, and five on cheek, chin, forehead and back. This tells the same story as Table IV., of past stimuli of cold and warmth.

6. Table VI. deals more elaborately than the others with double sensation in different areas of the skin, the tip of the tongue being the most accurate in this respect of all examined, and the tip of the index finger next, which is to the great toe as 2.3 to 11.3, the palmar surface of a finger half as accurate again as the dorsal surface, the palm of the hand twice as accurate as the surfaces of the forehead and back of ankle, nearly four times as much so as the dorsum of the foot and six times as the skin of the middle of the back.

There is here a very close relation between the amount of exposure of these various regions to tactile stimuli and their present equipment of ability to discriminate between two small objects.

7. Table VII. deals with the sensation of pressure in certain groups of areas, and shows that change of pressure is perceived about three or four times as accurately on the forehead, lips and tongue, as on the finger nail, back of forearm, hand, or fingers, and more than three or four times on the back of the foot, and sole, and surface of leg and thigh. In this group of observations also the rule is followed that the greater and more frequent in man’s ancestral past have been the exposure of his skin to variations of pressure, the greater is his present power of accurate discrimina­tion of them.

There are some scattered facts mentioned by Professor Sherrington which are in keeping with the line here taken, that the formation of receptors in the skin have their origin in accumulated stimuli. He refers to the vain endeavours of Goltz to evoke the reflex croak of the female frog by applying electrical stimuli to the skin, whereas non-nocuous mechanical stimuli were the only stimuli that proved effective.