142 GRAND STRATEGY OF EVOLUTION 



for example, or those which in the mammals are regul- 

 arly supplied to the foetus by the circulating maternal 

 blood, may be some millions of times greater than that 

 in the lower ones. The difference in the Tightness is 

 not so easily measured, but consideration of all the 

 numerous factors involved may convince one, perhaps, 

 that it is of a commensurate order. 



4. The Nutritive Income and Forage Dividends of 

 Youth. To the working capital deposited in the egg, 

 or provided for the embryo by placental nutrition, may 

 be added further endowments in the form of post-natal 

 income and forage dividends. They are derived, in 

 part, from secretions of the parent body, such as mam- 

 mary glands and other organs, cooperatively adjusted" 

 to cosmic, climatic, and germ cycle periods; and in 

 part from a percentage of the raw materials captured 

 by the parents, or by the social group. All these re- 

 sources are subject to draft at sufficiently frequent ancf 

 regular intervals; and the income from them is better 

 insured, increased in volume and variety, and spread 

 over a longer and longer period of growth, with the 

 progress of evolution. Here also the great increase in 

 the volume and Tightness of parental endowments is 

 one of the most striking phenomena in evolution, and 

 long familiar to even the most casual students of nature. 



IV. Bisexual Cooperation as an Agency in Parental 

 and Social Benevolence 



i. Sex, and Sexual Divergence. Let us consider 

 for a moment the respective roles played by sex in the 

 growth and organization of life. 



The characteristic differences between males and 



