INTRODUCTORY 5 



proved that man already existed : he had already been developed, 

 according to the theory, from a lower ape-like form, now extinct. 

 Flint instruments, showing unmistakable signs of human work- 

 manship, have been found in deposits that belong to a preglacial 

 age. 1 Apart from such proofs it is evident from the stage of 

 development that man had reached at the beginning of the quater- 

 nary period that he must already have been man, properly so- 

 called, in the tertiary. 



If we subdivide the tertiary period into three, we find further 

 evidence of evolution. In the first of the three, the Eocene, we 

 find animals and plants belonging to families now existing. In 

 the second, the Pleiocene, existing genera are represented, but 

 not yet species that are still extant. Finally, in the third, 

 the Pleistocene, we find animals (among them man) and plants 

 representing species that are now living upon the earth. 



(d) In the quaternary age existing species are found in 

 abundance, and frequent evidence of man appears. 



(3) There is the evidence of comparative anatomy and 

 physiology. An impartial anatomist must put man at no great 

 distance from the higher apes, whether he compares their 

 bony skeleton, or their bodies generally. Even their brains 

 agree in structure, though in man the development is 

 enormously greater. Comparative physiology shows that the 

 processes of life in all animals are, roughly speaking, the 

 same : all of them take in protoplasm as food : all of them 

 make use of the oxygen in the atmospheric air or of that dis- 

 solved in water in order to oxidise the tissues they have built 

 up, and so produce heat and energy. There is one mode of 

 reproduction common to all. 



(4) The present geographical distribution of animals and 

 plants is explicable on the theory of the gradual evolution of 

 species (beginning at some one centre) and their gradual dis- 

 persal to all accessible regions. Whereas, on the theory of 

 special creation, why have oceanic islands only those animals 

 which had the power of making their way thither over the 



1 See Natural Science for April 1894, Nov. 1897, Jan. and Feb. 1898. The con- 

 troversy seems to prove conclusively the existence of Plateau Man. 



