Effects of Temperature on Tropical Marine Animals. 



II 



This result is confirmed by taking the average of all five rings; for here 

 also the increase in rate is in the form of a straight line practically coinciding 

 with that displayed by Ring A. This average curve is shown in figure 3. The 



17 18 J9 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 



Degrees Centigrade 



Fig. 3, illustrating Table I. 



equation for the increase in rate with elevating temperature between 17.5° 

 to 35° C, in these rings, is y = 4.85X + 54-5 and for Harvey's ring it is 

 y = 6.66x + 50; where y is the rate at any given temperature above 17.5°, 

 but below 30° in Harvey's and 35° on my curves, x is the temperature- 

 increment. Thus at 25.5° C.x = (25.5 — 17.5) =8, and at 27.5° C. x = 10, 

 etc. The constants 54.5 and 50 are the rates of the rings at 17.5° C. 



Above 33° C, Harvey observed a sudden decline in rate, but my rings 

 did not display this decline until they had been heated to 35.5° to 39**, and 

 Ring A did not display it even at 39° C. 



As Harvey states, these curves bear a close, although possibly only a 

 superficial, resemblance to those of enzyme actions. 



Certainly our observations are not in accord with the conditions necessi- 

 tated were the rate of the nervous impulse a simple chemical reaction, for 

 in this case the curve would be given by an equation of the form y = ac', 



