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ANN HAVEN MORGAN 



the normal foot never failed to react to touch except in two cases, 

 clearly caused bj^ a faulty technique. The cocained foot failed 

 to react to the strike of the falling shot at any time (table 8), 

 but both the normal and cocained foot reacted regularly and with 

 the same retardation which had been affected by the cocaine in 

 previous experiments (tables 4, 5). The conclusion is that 

 independent heat receptors are present in the foot of the frog 

 and that a complete separation of the touch and the heat sense 

 had been affected. 



TABLE 9 



Responses in seconds to pain and heat. Pain stimulation by imcking outer side 



of fifth toe. Feet normal. Reaction allowance, 30 seconds. 



Stimulation time, 2 minutes 



Independence of the responses to pain and heat. The method 

 used in this separation was dipping the foot in water at 40°C. 

 and pricking the skin on the outer side of the fifth toe. No degree 

 of heat higher than 40°C. was used, because of the possibility 

 that the higher degrees of heat might be painful and the two 

 responses thus confused. Pricking the web between the third 

 and fourth toes was first tried, the particular web being quite 

 arbitrarily selected for stimulation. In some cases the foot 

 would react to pricking done anywhere on this web, in other 

 cases it would react to it in certain areas only, and in still other 

 cases the foot would fail or almost fail to give any reaction at 

 all to pricking anywhere on this web. Other webs were after- 

 ward tried with much the same result. When the skin on the 



