Biological Struggle for Existence 217 



an inadequate supply, the competition taking the form 

 either of direct struggle of one animal with another, or 

 death from mere lack of something necessary on the part 

 of some. This conception has been broadened with the 

 development of the theory to include the other less Mal- 

 thusian forms. 



If we consider the three forms of struggle pointed out 

 above, as together making up the conception, we may for 

 convenience designate it as ' biological ' struggle, inasmuch 

 as individuals are directly brought into conflict with one 

 another for life and death, and as moreover the end is not 

 attained through the struggle alone, but requires the further 

 biological function of reproduction to make it effective. 



In greater or less contrast with this, we find other cases 

 in which there is a shading one way or the other away from 

 this form of competition with its indirect results. On the 

 one hand, there are certain hypotheses of a biological sort 

 which utilize the conception of struggle without distin- 

 guishing it clearly as a process preliminary to that of sur- 

 vival. In Roux' * struggle of the parts ' the conception is of 

 the relative determination of physiological processes by the 

 accentuation or development of certain cells and organs 

 at the expense of others. 1 It is analogous to the struggle 

 for food ; the idea being that there is a preferential sup- 

 ply of nourishment, blood whatever aids the anabolic 

 processes in these particular directions. But the mechan- 

 ism of it is entirely unknown. In Weismann's ' germinal 

 selection,' also, a similar reason for survival is postulated - 

 differences of some sort between germ-cells - - whereby 

 some of them are more favourably situated or otherwise 



1 Roux, Gesammelte abhandlungen uber Entwicklungsmechanik der Organ- 

 ismen, Vol. I. 



