PATHOLOGY OF SENSIBILITY 



Pathology of sensibility is one of the chief means used in 

 diagnosing and localising diseases of the nervous system. 

 Important work on this field of study has been done by 

 Henry Head and his co-workers in England. He examined 

 many cases of lesions of the peripheral and central nervous 

 system, where disturbance of sensibility was the most 

 prominent symptom. Topping his investigations was an 

 experiment, done on himself. One of the nerves on his 

 left arm was cut and then sewn by a surgeon. The dis- 

 turbances of sensibility, caused by the operation, and their 

 recovery were for some years carefully studied by him and 

 his friends. 



I take for granted that you know Head^s work, hence I 

 shall only refer to the principal points. 



In the opinion of Head, Rivers, Sherren and others there 

 are three chief means by which stimuli for sensibility are 

 caught up in the periphery. The first is deep sensibility, 

 which originates chiefly in the muscles and in the joints. 

 By this, impulses produced by pressure and by movements 

 are conducted to the central nervous system. 



The other two systems conduct stimuli, caught in the 

 skin and in the subcutaneous tissue. These systems are the 

 protopathic and the epicritic. The former responds to 

 painful cutaneous stimuli and to the extremes of heat and 

 cold. The latter, the epicritic sensibility, serves for light 

 touch, for discrimination of two points and for appreciation 

 of the finer degrees of temperature. 



This conception of Head and his co-workers was very 

 revolutionary and hence this theory has been much criticised. 

 In cooperation with one of my pupils — Dr. Schoondermark — 

 I examined at Amsterdam many lesions of the peripheral 



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