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ANN HAVEN MORGAN 



manner as with touch and cold, touch was verj^ easily eliminated, 

 and by reducing the cocaine treatment the cold sense could be 

 preserved (table 18) in a very effective condition. 



Independence of responses to acid and cold. The sensation of 

 cold was separated from the chemical sense in the skins of twelve 

 different frogs. After thirty minutes of treatment with cocaine 

 on the right foot the feet were alternately stimulated as usual. 



TABLE 17 



Responses of the foot to heat and cold. Right foot cocained 20 minutes. Left foot 



normal. Reaction allowance, 30 seconds. Stimulation time, 



2 minutes, co = no response 



The cold response was easily obliterated by the cocaine, but the 

 acid caused a sharp upward jerk at long or irregular reaction 

 intervals. This response itself seemed to differ little from that 

 of the normal foot. 



Independence of responses to pain and cold. Pain responses 

 were produced by pricking the skin of the frog on the side of the 

 fifth toe — a procedure that produced more regular results than 

 when the web was similarly stimulated. Care was always taken 

 that the needle did not go into the deeper tissues. The foot was 



