CUTANEOUS SENSIBILITY 



to the fact that appreciation of pressure is. lost in cutaneous 

 scars. 



Von Frey also suggested with much probability that the pain, 

 spots, which are most abundant in the skin, are served by the 

 free terminations of the superficial nerve-plexus, which supply 

 the epithelium of the Malpighian layer. It is possible that each 

 pain spot corresponds not with a single nerve-ending but rather 

 with a group of nerve-endings, otherwise the pain spots found by 

 v. Frey in certain regions would have to be much more numerous 

 and closer together. The fact that the cornea, which v. Frey 

 found to be destitute of any specific sensibility except pain, is 



B 



FIG. 19. Topography of areas sensitive to cold (A), and to warmth (B), on same part of the anterior 

 surface of the thigh. (Goldscheider.) The black areas are highly sensitive to thermal stimuli ; 

 the striated areas moderately so ; the dotted areas very slightly ; the spaces left white are 

 not at all sensitive to such stimuli. 



provided with a nerve-plexus that has free infra-epithelial endings, 

 as described by Cohnheim (1866), supports this conclusion. 

 Similar nerve - endings have also been recently described in 

 epithelium which is not ectodermal in origin, and in the interior 

 of many tissues which increases the probability that they are 

 related to pain sensibility, as this, when very slight, is allied to a 

 sensation of tension or of simple contact, as Nagel (1895), in oppo.- 

 sition to v. Frey's view, observed in the cornea. 



It is far less easy to identify the peripheral organs that 

 subserve the sensations of heat and cold. By elimination it may 

 be said that Dogiel's corpuscles, Kuffini's papillary endings, and 

 the Golgi-Mazzoni corpuscles are the organs for the sensation of 

 cold, while Pacini's and Kuffini's corpuscles function, at least in 

 the skin, as organs for the sensation of heat. The fact that the 



