364 lotka: efficiency in organic evolution 



pla}^ in the operation of the receptor-effector system, and have 

 grasped their bearing upon the fitness of the organism. 

 Quantitatively our problem may be stated in this form: 

 If r is the rate of increase per head per annum of a given type 

 or group of organisms, it is required to find a mathematical 

 expression, in terms of suitably chosen characteristic properties 

 of the organism and of the system of which it forms part, for 



"■ ■ (1) 



d 



e 



where e denotes an error of a specified kind, either of observa- 

 tion, operation, mentation or valuation. 



At the time when the tabular statement of the qualitative 

 analysis recapitulated above was first given, this was done in 

 the hope that such a provisional analysis might be found to 

 furnish the basis for a quantitative treatment of the subject. 

 This hope has since been realized, although it has been found 

 that in a sense the analysis had been carried too far. In order 

 to make any headway we must now in a measure retrace the 

 steps of our analysis, and recombine some of the threads which 

 we had unraveled. 



Let us note first of all that it is not so much isolated and 

 perhaps peculiar actions which interest us, but rather those 

 systematic actions which are of a more or less regular or routine 

 occurrence and which are aimed to meet some more or less 

 permanent demand. In such case, we can say in mathematical 

 terms that the actions in question serve to maintain a certain 

 parameter Xj at a value Xi (for example X] may be the annual 

 production and consumption of wheat, or the deathrate from 

 malaria etc., etc.). 



Disregarding, then, isolated and peculiar actions (which upon 

 reflection are found to constitute at most only a small proportion 

 of the activities of the organism), we may describe in a clear 

 quantitative way the general scope of the activities of a given 

 type of organism, such as man, by stating that the represen- 

 tative individual of that type so distributes his labor, that 



