408 THE EVOLUTION OF MAN. 



of the earth, during the many millions of years, in the 

 course of which organic life has been developing on our 

 planet, modifications in the mode of germination have 

 occurred in most animals ; this fact was first clearly recog- 

 nized by Fritz ]\Iuller-Desterro, and was thus expressed 

 in his able work, " Fiir Darwin." " The historical record 

 preserved in the history of the evolution (of an individual) 

 is gradually obliterated, in consequence of the fact that 

 evolution continuallv strikes out a straighter road from 

 the egg to the perfect animal, and the record is much 

 vitiated by the struggle for existence which the freely- 

 living larvas have to undergo." The former phenomenon, 

 the obliteration of the ontogenetic epitome, is effected by 

 the law of simplified or abridged heredity. The latter phe- 

 nomenon, the vitiation of the ontogenetic epitome, is caused 

 by the law of modifiied or vitiated heredity. In accordance 

 with this latter law, the young forms of animals (not only 

 freely -living larvae, but also embryos enclosed in the mother's 

 body) may be modified by the influence of the immediate 

 surroundings, just as fully formed animals are modified by 

 adaptation to the external conditions of their existence; 

 the very species are sometimes modified during germination. 

 In accordance with the law of shortened heredity, it is 

 advantageous to all higher organisms (and the more so the 

 higher their development) that the original course of 

 development should be shortened and simplified, and, 

 consequently, that the ancestral traditions should be 

 obliterated. The higher the individual organism stands in 

 the animal kingdom, the less completely does it reproduce, 

 in its Ontogeny, the entire series of its ancestors, for 

 reasons which arc partly known, partly yet undiscovered. 



