MULTIPLICATION OF THE HUMAN RACE. 519 



may cause a larger absorption of heat from the burning mass 

 or the hot gases it gives off; and the extra steam generated 

 by this extra heat will, as before, augment both the motive 

 force and the emission through the safety-valve. And this 

 last case of coincident variation, is parallel to the case with 

 which we are here concerned the augmentation of individual 

 expenditure and of reproductive energy, that may be caused 

 by a superiority of some organ on which the utilizing or 

 economizing of materials depends. 



Manifestly, therefore, an increased expenditure for Gene- 

 sis, or an increased expenditure for Individuation, may arise 

 in one of two quite different ways either by diminution of 

 the antagonistic expenditure, or by addition to the store which 

 supplies both expenditures; and confusion results from not 

 distinguishing between these. Given the ratio 4 to 20, as 

 expressive of the relative costs of Genesis and Individuation ; 

 then the expenditure for Genesis may be raised to 5 while the 

 expenditure for Individuation is raised to 25, without any 

 alteration of type, merely by favourable circumstances or 

 superiority of constitution. On the other hand, circumstances 

 remaining the same, the expenditure for Genesis may be 

 raised from 4 to 5, by lowering the expenditure for Indi- 

 viduation from 20 to 19: which change of ratio may be 

 either functional and temporary, or structural and per- 

 manent. And only when it is the last does it illustrate that 

 inverse variation between degree of evolution and degree of 

 procreative dissolution, which we have everywhere seen. 



370. There is no reason to suppose, then, that the laws 

 of multiplication which hold of other beings, do not hold of 

 the human being. On the contrary, there are special facts 

 which unite with general implications to show that these 

 laws do hold of the human being. The absence of direct 

 evidence in some cases where it might be looked for, we find 

 fully explained when all the factors are taken into account. 

 And certain seemingly-adverse facts prove, on examination, 



