GENESIS OF THE NERVOUS SYSTEM 39 



mechanics. Therefore E. Haeckel's theory of the 

 gastrula, confirmed by comparative embryology, 

 phylogeny, and ontogeny, shows that the gastrula 

 stage exists in all animals in the embryonic period, 

 even if it be momentary ; and thus the animal 

 descent from the sponge to man is demonstrated 

 by the great biogenetic law of Haeckel. Thus it 

 can be deduced that if man has an ancestral claim 

 to such primary metazoa as sponges, both they 

 and man are the outcome of the universal 

 mechanics. Thus, just as in the first period of 

 animal life in the world the gastrula represented 

 the future of man, so in the epithelial cell of the 

 ectoderm of the said gastrula there was represented 

 in germ that which in time to come was to be the 

 human intelligence. 



But man has a still more elementary origin : the 

 gastrula is a double line of cells ; it is an enormous 

 advance if we compare it with the morula, which is 

 a conglomeration of cells arranged in a spherical 

 shape ; here one finds no difference between the 

 internal and the external covering. 



The morula is an anterior stage to the blastula, 

 as it has a more backward place in the cell. This 

 primitive form is still preserved by the human 

 species, for the human being rises from the union 

 of the zoosperm and the ovule. Thus man meets 

 his ancestors on the very borderland of the in- 



OF THE 



UNIVERSITY 



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