90 



ANN HAVEN MORGAN 



(table 1) only the right foot was stimulated and the left served 

 as a check. The right foot was first immersed in water at 30°C. 

 and at intervals of two minutes after that in baths increasing 

 each time by 1°C. from 30°C. to 50°C. : no responses occurred 

 below 39°C., and in some instances none below 43°C. As the 

 heat was increased the vigor of the response was also increased 



TABLE 1 

 Reaction intervals in seconds of frogs' right feet subjected to temperatures ranging 

 at one degree intervals from 30° to 50°C. No reactions {indicated by °o) were 

 obtained at temperatures of 38° or lower, hence this part of the table is condensed. 

 Feet normal. Reaction allowance, 30 seconds. Stimulation interval, 2 minutes 



and the reaction interval became shorter and shorter. The heat 

 response was a vigorous upward jerk of the foot, so uniform that 

 usually no attempt to describe it has been made except by the 

 word 'jerk' and the statement of the length of the reaction in- 

 terval, i.e., the time between the application of the stimulus and 

 the reaction itself. 



The next step was to discover whether there would be different 

 results if the heat was applied with differences of temperature 



