no 'Journal of Co?nparative Neurology and Psychology. 



fingers can not be moved voluntarily there will be a loss of sensibility 

 to movement passively produced. Some of these effects may be found 

 over a variable extent of the palm and the back of the hand. In 

 rig. 1 is given the condition found in a man following an operation 

 in which part of the ulnar nerve was excised. The area insensitive 

 to light touch and to the intermediate degrees of temperatures in- 

 cluded all the little finger, about three-quarters of the ring finger, 

 and about two-fifths of the palm and back of the hand. Part of 



Fig. 1. — The extent of loss of sensation following the division of the ulnar 

 nerve at the elbow. The part marked with horizontal lines was insensitive 

 to light touches, and to intermediate degrees of temperatures. The vertical 

 line area (cross-hatched on account of its being included within the area 

 insensitive to touch), was, in addition, insensitive to pressures and to pain. 

 Adapted from Head and Sherreu. 



this area was insensitive to deep touch and no sensation was got from 

 the vibrations of a tuning fork. This area was also analgesic. 



In this and other cases in which losses of sensibility were found, 

 the ability to appreciate touch was tested with a wisp of cotton wool 

 lightly brushed over the parts. When such a piece of cotton wool 

 is carried over the skin of a normal individual, there is a distinct 

 feeling of touch, which is magnified, perhaps altered, wherever 

 the hairs are touched. The cotton wool should be very lightly 

 grouped in a bundle, not tied, and I have found that on the hand 

 a piece of cotton wool, weighing 55.5 mg., with a bending pressure 

 of from 200 to 300 mg. will be accurately appreciated over the parts 



