690 Studies in the Theory of Descent. 



striking difference between this view and the 

 phyletic composition of the animal (and vegetable) 

 kingdom out of physiological individuals (Haeckel's 

 " Bionten"), since contemporaneous animals (in- 

 dividuals and species) are known to influence one 

 another in the most active manner. 



Now if we further consider that the same units 

 (cells) which, by their reproduction and division 

 of labour, at present compose the body of the 

 highest organism, must at one time have consti- 

 tuted as independent beings the beginning of the 

 whole of organic creation, and that consequently 

 the same processes (division of cells) which now 

 lead to the formation of a mammal, at that time 

 led only to a long series of different independent 

 beings, it will be admitted that both develop- 

 mental series must depend upon the same inciting 

 powers, and that with reference to the causes of 

 the phenomena it is not possible that any great 

 gap can exist between ontogeny and phylogeny, 

 *. e. between the life-phenomena of the individual 

 and those of the type. According to our view 

 both depend upon that co-operation of the same 

 material physical forces which admits of being 



between the struggle for existence and survival of the fittest 

 in individuals and species, and the struggle for existence and 

 survival of the parts in the individual organism. See " Der 

 Kampf der Theile im Organismus : ein Beitrag zur Ver- 

 vollslandigang der mechanischen Zweckmiissigkcitslehre," 

 Leipzig, 1 88 1. R. M.] 



