398 



lotka: efficiency in organic evolution 



Let us write (17) in the form 



(vE + v'E')dL = 

 vE + v'E' = 



(18)1* 

 (19) 



The problem before us is, Suppose the individual values the 

 commodity not at v per unit, but 2bi v + be, what will be the 

 effect upon r? 



We have: 



(20) 



5r = —be 

 be 



dr dx 

 bx be 



be 



(21) 



Fig. 1 



Consider a graph (see figure 1) : 



y = vE + v'E' 



y' = {v + be) E + v'E' 



If the individual acted in accordance with the curve y, the 

 true curve, he would consume 



(24) 



(22) 

 (23) 



X = OP 



dx 



"The quantity E=--t in equation (18) measures marginal efficiency and 

 thus differs from Ey in equation (4), which measures total efficiency. 



