2l6 "Journal of Comparative Neurology and Psychology. 



which remain endowed Avith nidtor nerves are sensitive to pressures 

 and jarrings of the skin, but in his own case Head found that in 

 this region "when the hairs are puUed the elevation of the skin 

 produced no effect upon consciousness," land also', that "pressures 

 which had previously caused a sensation were no longer appreciated 

 when applied to the skin lifted from the subcutaneous structures to 

 form a ridge."" It is evident, therefore, that the sensations produced 

 by stimulation of the hairs are not pressures and do not belong to the 

 class of "deep sensibility." On the other hand. Head and Sherren 

 found that with the return of ]n-otopathic sensibility — the ability 

 to appreciate prick as such and to respond to ice and to water at about 

 50° C. — "the hairs began to react to cotton wool, and this stimulus 

 evoked a curious radiating sensation with a characteristic quality. 

 True localization was impossible and the skin over the same parts 

 became, when shaved, entirely insensitive to cotton wool."^ In 

 another place we are told "under certain conditions the hairs may 

 regain a peculiar form of sensibility at the time when the affected 

 parts are sensitive only to prick and to the extremes of heat and cold. 

 , Plucking a normal hair, will, in most cases, cause pain, and it is 

 this sensibility to pain that returns to the hairs when they react in 

 this manner to stimulation with cotton wool."^ These facts indicate 

 that the sensations from the hairs are to be grouped not with the 

 epicritic, although they react to cotton wool, but among the proto- 

 pathic forms of sensation. 



The subject of my experiments is an individual in whose arm the 

 median and ulnar ner\'es had been cut about four months previous 

 to the examinations.^ To assist in the definition of the area in 

 which protopathic sensibility remained and from which the epicritic 

 sensibility had departed, I carefully examined the hairy parts of 



^'H. Head, W. H. R. Rivers and J. Slierren. The Afferent Nervous System 

 from a new Aspect. Brain, 1905, vol. 28, p. 303. 



"H. Head and J. Sherren. The Consequences of Injury to the Peripheral 

 Nerves in Man. Brain, 1905, vol. 28, p. 241. 



*Head and Sherren. Op. cit., p. 242. 



'For an account of the lesions and general sensihility changes see my article 

 in Joiir. Cotnp. Neurol, and P.sijrhol., 1909, vol. 19, pp. 107-124. 



