428 Dynamic Theory. 



succeeded by a motion of brain cells called sensation of heat. The 

 researches of Blix and Groldschneider appear to show that changes 

 of pressure and of warm and cold temperature are perceived through 

 different points of the skin. "The feeling of pressure seems to be in- 

 timatel}' associated with the hairs, which is not the case with sensations 

 of temperature. These three sets of points indeed are so near together 

 that the separation had hitherto not been observed, especially as they 

 are so closely intermixed." " Groldschneider experimented with a fine 

 point which he passed over the skin, thus testing it, sometimes for pres- 

 sure, sometimes with a warm point for heat, sometimes with a cold 

 point for cold. Moreover, if he raised the points of skin thus deter- 

 mined, with a fine needle, and snipped off the fragment of the skin, he 

 ^ound that the resulting sensation was quite different in the three cases. 

 If the point removed was a pressure point, the sensation was one for the 

 moment of pain, while the temperature points gave sensations respectively 

 of heat or cold. The terminations of the temperature nerves are, according 

 to Groldschneider, much finer than those of the pressure nerves, and they 

 are also fewer in number. He cut from his own skin a large number of 

 sensitive points, but while he found that each corresponded to a nerve 

 end, he was not able to discover any difference at or in the termina- 

 tion of the nerves corresponding to these different sensations, though it 

 may reasonably be expected that such must exist. The question has 

 arisen whether there are separate nerve endings for pain as apart from 

 pressure, &c. , but the observations of Blix and Groldschneider appear to 

 show that pain arises merely from the intensification of other impres- 

 sions and that it does not reside in any special organs." 1 



These researches of Blix and Groldschneider seem to show a differen- 

 tiation of the temperature-points of the skin into two classes one class 



FIG. 169. A patch of skin on the back of the 

 hand showing position of points of sensation. 

 C P. Points sensitive to cold. 

 W P. Points in same patch sensitive to warmth. 

 H. Position of Hairs, the points sensitive to 

 pressure. ( After Blix and Goldschneider. 



FIG. 169. 



sensitive to warm stimulations and the other sensitive to cold stimula- 

 tions by which I understand stimulations above and below the ordinary 

 temperature of the body. The three square figures illustrate this, CP 

 showing the points on a single patch of the back of the hand irritated 

 by the cold stimuli ; WP, those affected by the warm stimuli, while H 

 shows the position of the hairs on the same patch. It may be that it is 

 the stimulation of the "cold points" which is transferred to. the little 

 muscles of the hair follicles causing the phenomenon of " horripilation," 

 or goose skin, these points being movable only by the heavy long waves 

 of very low temperature. ( See chapter on Emotion. ) 

 1 Lubbock Animal Senses, p. 10. 



