TEMPERATURE SENSES IN FROG S SKIN 



107 



Independence of the responses of cold and heat. Cold and heat 

 sensation are separable by exhaustion of the cold receptors and 

 by treatment with cocaine. The right foot was each tune 

 ininiersed for twenty minutes in the solution of cocaine and the 

 right and left feet were then stunulated by water at 2°C. and 



TABLE 16 



Responses in seconds of the foot to decreasing temperatures . Right foot cocained 



30 minutes. Left foot normal. Reaction allowance, SO seconds. 



Stim^ulation time, 2 minutes, oo = no response 



4o^C. (table 17). Responses to cold entirely ceased; those to 

 heat remained ^dgorous wdth a lengthened reaction time. 



Independence of responses to touch and cold. The ease with 

 which the sense of touch disappears from the skin has already 

 been mentioned in connection with touch and heat. 



In that case responses to touch failed after the foot was im- 

 mersed in cocaine 10, 15, 20 and 25 minutes, but reaction to 

 water at 45°C. remained retarded but vigorous. In the same 



