122 'Journal of Comparative Neurology and Psychology. 



the ulnar side from a line drawn tlirongh the middle of the ring 

 finger; the superior radial nerves presumably the radial side to 

 a line dra\^al through the middle of the thund); while the remainder 

 of the palmar part of the hand is innervated by the median nerve. 

 All of these areas must have, according to Head, deep, protopathic 

 and epicritic sensibilities. But Head's work shows that Ave seldom 

 find areas of these different fomis of sensibility occupying the same 

 position on the hand. For the median, for example, there may be 

 a loss of deep sensibility in the first and second fingers; but the rest 

 of the area which is assigned to the median retains its deep sensibil- 

 ity. The retention of this sensibility must be due to fibers in other 

 nerves. So also we find there is an overlapping of the epicritic 

 sensibility, and it seems to me the results on H, as well as the results 

 olitained by Head, clearly show such an overlapping effect. On the 

 arm, the areas A, B and C, Fig. 3, were supposed to retain all 

 their epicritic sensibility, whereas it is evident that areas B and C 

 are not nearly so sensitive as area A. 



The tests for threshold of pain sensations brought out no new 

 facts. The areas which were carefully examined for touch thresh- 

 olds, and which gave the results recorded above, were examined, 

 but, with perhaps a slight increase in threshold over the whole lower 

 arm on the left, there was nothing distinct. The measurements 

 made with the algometer described above showed that in the area 

 near the elbow (rectangle in Fig. 3) for, each horizontal centimeter 

 above the line of loss of deep sensibility there was no difference. 

 The averages of three experiments in each longitudinal area are 

 as follows: 9Y8, 905, Y79, 820, 970, and 923 grams. Similarly 

 on the hand there were no sufficiently noticeable differences between 

 the threshold in area B (Fig. 5) from that in area F. 



The pains on movement of fingers, wrist and elbow are of a 

 different character from those produced by pressure, and they have 

 been mentioned in an early part of the article. They were not 

 located at the place where the movements occurred, but were always 

 referred to the fingers or hand. It seems likely that these were 

 due to pressure on the nerve trunks, but this is purely speculative 

 and is supported by only a few observations as follows: At times 



