MECHANISM OF PROCESS OF DEATH 61 



amount of M (this was called M^) which diminished dur- 

 ing exposure, and the. amount remaining at the time T 



v' nn 



is Moe ^ . If this is added to the amount of M pro- 

 duced from A during exposure we get (substituting the 

 value Mo=90) 



Total amount of m=2700(^^) {e-^'^-e-^''^)+goe-^''^ 



and since Net Resistance = M + 10 (because the base line 

 of the curve is taken as 10) we have ^^ 



Net Resistance = 2700 ( „ V ) ( e~ "'^^^ - e~ ^^^ ) + 90e ~ '^^^ + 10 



If we calculate the resistance by means of this for- 

 mula we get the curve given in Fig. 28, which shows a 

 close agreement between the observed and calculated 

 values. It is therefore evident that, whether our picture 

 of the underlying mechanism is correct or not, it leads 

 to an equation which enables us to predict the death 

 curve with considerable accuracy. The predictive value 

 of the equation is quite independent of the assumptions 

 which led up to it, and while it creates a presumption 

 in favor of these assumptions, it of course does nothing 

 more. It is hardly necessary to emphasize that equations 

 which enable us to predict the course of vital pro- 

 cesses are a prime necessity in biology, since they make 

 it possible to employ the methods by which the exact 

 sciences have been able to make rapid progress. 



It is evident that we are able to follow the progress of 



jr fp K T 



" The values e i and e ^ may be obtained from Table IV 



in the Smithsonian Mathematical Tables, Hyperbolic Functions, by G. F. 

 Becker and C. E. Van Orstrand, 1909. iSee also Mellor, J. W. (1909) pp. 

 le, 08, 118. 



