EVOLUTION OF THE HUMAN SPECIES 155 



does the human body develop? Does palaeontology 

 throw any light on the antiquity of man? Do the 

 rules of nature's order control the lives of men? Our 

 course is now clear; we shall take up serially the 

 anatomy, embryology, and fossil history of the human 

 species, in order to see that there is ample proof of the 

 actual occurrence of evolution, and then, as before, 

 we may look about for the causes which have produced 

 this result by natural methods. 



While it is necessary to treat the subject directly, 

 namely, by examining the actual evidences relating 

 to the particular case in question, it is worthwhile before 

 doing so to point out that, as the whole includes a part, 

 human evolution has already been proved beyond 

 question. This conclusion must be accepted, unless 

 reasons can be given for excluding mankind from the 

 rest of the living world as an absolutely unique type, 

 supreme and isolated because of some peculiar endow- 

 ments not shared with the rest of .animate nature. If 

 these reasons are lacking, and the unity of organic 

 nature be recognized, human evolution cannot be denied 

 unless some interpretation more reasonable and logical 

 than evolution can be given for the whole mass of facts 

 exemplified and discussed in the foregoing chapters. 

 We may accordingly approach the main questions by 

 asking if there are any reasons for regarding the human 

 species as a unique and isolated type of organism. 



At the outset, we must recognize that in so far as 

 the human body is material, its movements and mass 

 relations are controlled by physical principles, like all 

 other masses of matter. It is well, indeed, that this is so, 

 for if gravitation and the laws of inertia were not con- 



