224 'Journal of Comparative Neurology and Psychology. 



said that if the area of the skin which is stimulated has a few spots 

 that ordinarily give an intense sensation of coolness or warmth, 

 the areal stimulation takes this character and that the spots which 

 normally give a weaker sensation help to fill up and to make the 

 areal stimulation continuous. In other words*, it is assumed that 

 when more than one spot is stimulated, the general character of 

 the resultant sensation depends upon the sensation that is most 

 intense in the spots stimulated." 



It will be remembered that in their examinations of sensations 

 following nerve injury. Head and his collaborators found certain 

 sensation losses that appear not to confonu with the hypothesis of 

 special nerve endings for warmth and coolness alone. Certain of 

 their results appear unaccountable on the supposition of loss of 

 certain numbers of the fibers that supply the end organs concerned 

 with the sensations of warmth and cold, — supposedly Ruffini's cylin- 

 ders and Krause's end bulbs, respectively. Their work has cast 

 considerable doubt on the singularity of the sensations of warmth 

 and coolness and it appears from their examination of cases in which 

 nerves have been injured or cut that there are two sets of nerx^es, 

 four different fibers, which convey temperature sensations. The 

 two sets belong respectively to the epicritic and protopathic systems, 

 the former being concerned with medium temperatures, which are 

 appreciated as warmness and coolness, while the latter mediates the 

 sensations which may be spoken of as hotness and coldness.^" 



The results of temperature experiments made by me on a patient 

 (H.) in whose arm the median and ulnar nerves were cut confirm, 

 in a general way, those reported by Head." In some particulars, 

 however, differences were found. 



Over parts which were insensitive to pressures no sensations of 

 temperature were obtained, even from those temperatures which 

 caused a burning of the skin. H. at one time placed his hand 



''On this see Titchener. Ea-pcrhiicntal Psi/cliologi/, vol. 1, part 2, pp. 87-91. 



"Head and Sherreu. The Consequences of Injury to the Peripheral Nerves 

 in Man. Brain, 1905, vol. 28, pp. 224-228. 



"For an account of the patient and for other sensation differences, see Franz : 

 this Joiinuil. vol. 19, pp. 107-124. 



