SENSATION'S FOLLOWING NERVE DIVISION. 



SHEPHERD IVORY FRANZ. 



From tJic Lahoralorics of the Government UospUal for the Insane, 

 Washington, D. C. 



With Five Figures. 



I. TilE PlU<:SSUEE-LIKE SeNSATIONS. 



Since the confirmation and elaboration by Goldscheider, by von 

 Frej and by others, of the discovery of Blix that there are jwints 

 or areas on the skin sensitive only to certain forms of stimulation, 

 physiologists have assumed a form of punctate sensibility in the 

 skin. The work of these investigators has been taken to show that 

 in the skin special nerves subserve the following sensations : heat, 

 cold, pain and pressure (touch). On the other hand, the recent 

 work of Head and his co-workers has not only cast considerable 

 doubt on the validity of the broad generalization of punctate sen- 

 sibility, but it is also plain that the earlier hypothesis is not in 

 accord with the results obtained on man after injury or section of 

 peripheral nerveSi. 



Head, it will be remembered, investigated the sensibility to light 

 touch, to different degrees of temperature, to pressure, to dual 

 stimuli, to pain, to size and to movement in patients following 

 injury or section of perij^heral nerves and he carried his inquiries 

 up to the point of recovery for all forms of sensation. The criticism 

 of the older hypothesis, which was made possible because of these 

 recent pathological studies, may well be summed up in the words 

 of Head: ''When the median nerve is divided, sensation is entirely 

 lost over a considerable part of both index and middle fingers. Over 

 the palm, within the area said by anatomists to be supplied by this 

 nerve, sensation is usually diminished and not completely abolished. 



The Journal of Compaeative Neurology and Psychology. — Vol. XIX, No. 1. 



