The Evolution of Man 87 



CHAPTER VI 



Thb Evolution of Man 



At the beginning of the last chapter I showed how 

 the embryonic development of an animal throws light 

 on its evolutionary ancestry. By some law, which I 

 prefer to regard as still quite unexplained, the individual 

 body must pass roughly through the series of forms 

 which represent the long series of its ancestors in past 

 time. The human body is subject to this law like all 

 other animal frames, and we will first see what we can 

 gather from its embryonic development in regard to the 

 evolution of the species. 



The ovum or germ of the human body is, in its 

 mature form, a single cell or globule of plasm about one 

 one-hundred-and-twentieth of an inch in diameter. It 

 is surrounded by an elaborate membrane that quite cuts 

 it off from the one-celled Protozoa ; but if we go further 

 back to its immature form — say in the ovary of a baby 

 — we find it a more or less irregular and amoeboid 

 particle about one two-hundred-and-fortieth of an inch 

 in diameter. In some of the lower classes of animals 

 the ovum actually creeps about like the Amoeba. Man 

 begins his existence as a " microbe " therefore, and it is 

 more wonderful that his complex frame should be built 

 up from this in the space of nine months than that such 

 an evolution should have been brought about in the 

 space of fifty million years. After fertilisation the single 

 cell grows into a cluster, and passes through the stages 

 I described above. But, for the reasons I gave, these 

 early stages are much complicated and modified in 



