14 THE KIDDLE OF THE UNIVERSE. 



towards their destruction and dissolution in one part 

 of space, others are springing into new life and 

 development in other quarters of the universe. 

 (5) Our sun is one of these unnumbered perishable 

 bodies, and our earth is one of the countless transitory 

 planets that encircle them. (6) Our earth has gone 

 through a long process of cooling before water, in 

 liquid form (the first condition of organic life), could 

 settle thereon. (7) The ensuing biogenetic process, 

 the slow development and transformation of countless 

 organic forms, must have taken many millions of years 

 — considerably over a hundred. 1 (8) Among the diffe- 

 rent kinds of animals which arose in the later stages 

 of the biogenetic process on earth the vertebrates have 

 far outstripped all other competitors in the evolu- 

 tionary race. (9) The most important branch of the 

 vertebrates, the mammals, were developed later (during 

 the triassic period) from the lower amphibia and the 

 reptilia. (10) The most perfect and most highly- 

 developed branch of the class mammalia is the order 

 of primates, which first put in an appearance, by 

 development from the lowest prochoriata, at the 

 beginning of the Tertiary period — at least three 

 million years ago. (11) The youngest and most 

 perfect twig of the branch primates is man, who 

 sprang from a series of man-like apes towards the 

 end of the Tertiary period. (12) Consequently, the 

 so-called "history of the world" — that is, the brief 

 period of a few thousand years, which measures the 

 duration of civilisation — is an evanescently short 

 episode in the long course of organic evolution, just as 

 this, in turn, is merely a small portion of the history 



1 Cf. my Cambridge lecture, The Last Link, " Geological Time and 

 Evolution." 



