112 EVOLUTION THE RESULT OF CHEMICAL FORCES. 



complexity of the carbon compounds in the life-centers, is quite 

 certainly one of the conditions and causes of organic growth. 

 It is natural therefore to suppose that the more complex those 

 compounds are, the higher will be the development that proceeds 

 from them. 



All the higher forms of the animate creation, all in which there 

 is any principle of progress or variation, reproduce by the union 

 of two sexual elements. There is thereby added some mysterious 

 force which starts cellular subdivision, and a new and indepen- 

 dent life. The constitution of the fecundated nucleus is most 

 certainly changed from the type of either parental germ, because 

 an offspring is formed that always differs more or less from either 

 or both sources of origin. It is then altogether probable that the 

 molecules of one sexual element conjoin their chemical forces to 

 the molecules of the other, thus creating a surcharged center of 

 forces sufficiently powerful to start into being a new and self- 

 unfolding life. Then whatever combinations of atoms, repre- 

 senting either parental ancestral or original traits, prove to be the 

 stronger in the two-fold elements, will rule the subsequent differ- 

 entiations. Sometimes from such unions hare sprung remarkable 

 and often valuable race varieties, called sports of nature, and 

 differing from anything that has ever preceded them. As such 

 variations occur most frequently among domesticated animals, 

 which are in exceptional conditions of food supply and freedom 

 from care or exertion, they may perhaps be naturally explained 

 as springing from some extraordinary increase or superposition of 

 atoms in the molecules of the impregnated germs which pro- 

 duced them. 



In like manner in the geological ages, I imagine that when the 

 suitable conditions have come about for a new step to be taken 

 in the grand advance of life-forms, nature has provided for it in 

 the simplest way imaginable, by merely piling a few more atoms 

 on the enormously loaded molecules of germinal protoplasm. 

 It might naturally be supposed that a higher quality of food 

 would increase the formula of the vital compounds derived from 

 it; and as a consequence the uniting germinal elements would 

 form a higher combination in the ovarian nucleus, thus causing 



