Ii8 Journal of Comparative Neurology and Psychology. 



no doubt of the presence of both cpicritic and protopathic sensi- 

 bilities do not show a normal amount of sensibility to this form 

 of stimulation. There is a gradual decrease in the loss or in the 

 dullness of sensibility from the area of cpicritic loss, Ave may sav 

 from area of complete sensibility loss, to the area in which no sensory 

 change, according to Head's methods, can be demonstrated. The 

 accompanying figure illustrates the conditions found on the hand. 



The area tested was carefully examined for hairs, and wherever 

 hairs were found, the ])art was carefully shaved. The part of the 

 area insensitive to cotton wool was mapped out and recorded on the 



Fig. 5.— To illustrate the sensibility of the hand determined by Bloch's 

 instrument, compared with the loss of pressure and light touch sensations. 



hand with red ink. The sensibility to pressure and to forms of 

 stimuli denoting the presence or absence of protopathic sensibility 

 Avas also tested and the areas of loss were marked on the part. 

 Points were then selected separate from each other by 1 cm. These 

 were also marked with red ink so that the stimuli could be eiven 

 at approximately the same spots each time. These points were 

 then examined with the help of Bloch's instrument illustrated above. 

 Five experiments were made on each point and on corresponding 

 points on the right hand. Table I gives the results of this form of 

 examination. The letters indicate the corresponding areas on the 

 left (nerve cut) and right hands. The figures give the averages of 



