486 STUDIES IN ADVANCED PHYSIOLOGY. 



The experiments made by Blix and Goldscheider proved 

 the existence of distinct temperature nerves, and showed 

 that there are on the body warm points and cold points, 

 and that whenever a warm point is stimulated, no matter 

 what the stimulus, a sensation of warmth results, while 

 when a cold point is stimulated, even though it be with a 

 warm object, a cold sensation results. These points are of 

 course normally so arranged that the cold points are more 

 easily affected by cold and the warm points by increase of 

 heat. It is possible, however, to use electrical stimuli to 

 affect both and so produce in one class cold sensations and 

 in the other warm sensations even though the temperature 

 in the meantime may have varied not a bit. 



These temperature nerves, however, do not end in special 

 nerve end-organs but in networks of fibers not wholly un- 

 like the dendrons described in connection with the central 

 nervous system. These warm and cold points are, therefore, 

 definite anatomical structures and it is possible by carefully 

 exploring the skin with a sharp-pointed instrument to desig- 

 nate these points and to make an exact map of the temper- 

 ature topography. 



Finally it seems probable that there is a distinct center 

 for cold sensations and another for warm sensations. The 

 probability of this is suggested by the fact that an arm or 

 limb, when subjected to pressure, and so has as we say 

 4 'gone to sleep," is still able to perceive warmth but is in- 

 sensible to cold. 



THE MUSCULAR SENSE. 



When the muscles are called into action one is clearly 

 conscious of a sensation coming apparently from these 

 muscles and informing one of their extent and degree of 

 contraction. It is perfectly easy for an individual with 

 closed eyes to determine exactly the position and move- 

 ments of his muscles. This can only be accomplished by 

 the mind's taking note of the sensory impulses that come 

 from the skin of the part moved and from the sensory 



