CHAPTER IX. 



COINCIDENCE BETWEEN HIGH NUTRITION AND GENESIS. 



352. UNDER this head may be grouped various facts 

 which, in another way, tell the same tale as those contained 

 in the last chapter. The evidence there put together went 

 to show that increased cost of self-maintenance entailed de- 

 creased power of propagation. The evidence to be set down 

 here, will go to show that power of propagation is augmented 

 by making self-maintenance unusually easy. For into this 

 may be translated the effect of abundant food. 



To put the proposition more specifically we have seen 

 that after individual growth, development, and daily con- 

 sumption, have been provided for, the surplus nutriment 

 measures the rate of multiplication. This surplus may be 

 raised in amount by such changes in the environment as 

 bring a larger supply of the materials or forces on which 

 both parental life and the lives of offspring depend. Be 

 there, or be there not, any expenditure, a higher nutrition 

 will make possible a greater propagation. We may expect 

 this to hold both of agamogenesis and of gamogenesis; and 

 we shall find that it does so. 



353. On multi-axial plants, the primary effect of surplus 

 nutriment is a production of large and numerous leaf-shoots. 

 How this asexual multiplication results from excessive nutri- 

 tion, is well shown when the leading axis, or a chief branch, 

 is broken off towards its extremity. The axillary buds below 



475 



