WALTER E. GARREY 



53 



The relative velocities with which the nerve cells form CO2 at dif- 

 ferent temperatures are also shown graphically in Fig, 1 . The curves 

 are obtained from data in Experiments A, B, and E of Table I and 

 are constructed by plotting the reciprocal of time in seconds multiplied 

 by a constant (1,500). These curves of chemical reaction velocities, 

 like those of rate of heart beat, are exponential and not linear functions 

 of the temperature. 



Certain exceptions to the rule that the temperature coefficients of 

 heart rate were large at low temperatures and decreased with a rise 

 of temperature have been reported by the author. We submit below 

 data which indicate an exception which likewise applies to the forma- 

 tion of CO2 by the ganglion. The ganglion in this case was the largest 

 obtainable weighing 32 mg. from a Limulus weighing 8| pounds. 



The above data show the usual temperature coefficient (Qio) equal 

 to about 2 for the range 17-27°C. but the coefficient for the upper 

 range, 27-37°C., is uniformly larger than that usually found in our 

 other experiments. It is also seen that after the first treatment of the 

 ganglion at 37°C. and then cooling to 27°, the rate of CO2 develop- 

 ment is somewhat slower than at 27° prior to the heating. This is 

 usual but it should also be noted that at the end of the experiment 

 the rate at which the carbon dioxide was developed was identical to 

 the initial rate at 27°C. It is evident from this result that even fre- 

 quent subjection of the ganglion to 37° did not cause injury but 

 produced effects which were entirely reversible in character. The 

 constancy of the coefficients ((2io) at different temperature levels in 



