2l8 Journal of Comparative Neurology and Psychology. 



and at the subsequent operation. The extent of this area is much 

 larger than the area of loss of protopathic sensibility as determined 

 by the methods of Head, and the extensive character of the change 

 led me to a more careful examination of parts of the area. Since 

 time did not permit the careful mapping of the whole area, I selected 

 for more careful work two areas, one on the volar side of the forearm 

 near the bend of the elbow, the other on the dorsal-ulnar side of the 

 arm near the wrist. 



Fig. 1. 



Fig. 1. — Diagram of hand and forearm of subject in whom uhiar and 

 median nerves were cut at elbow. Scars of original accident and of operation 

 shown above elbow. Area marked with vertical lines represents area in which 

 hairs are insensitive to plucking. The diagram was made from a tracing of 

 a photogi'aph, and the distortion of the hand is due to the peculiar position in 

 which the patient holds the fingers. 



An illustration of the upper of these two areas as it Avas marked 

 in red ink on the arm of the subject is given in Fig. 2. The line 

 separating the area of pain-on-pulling-hairs from that of no-pain-on- 

 pulling-hairs is approximately that between areas D and E. In 

 general contour, however, it is more irregular and more nearly ap- 

 proaches the shape of the lowest line on the figure. The extent of 

 this area in which pulling the hairs did not result in a sensation of 



