220 THE DESCENT OF MAN [Part I. 



yet all must equally be ranked as species. So again the 

 species within the same large genus by no means resemble 

 each other to the same degree : on the contrary, in most 

 cases some of them can be arranged in little groups round 

 other species, like satellites round planets. 19 



The question whether mankind consists of one or sev- 

 eral species has of late years been much agitated by an- 

 thropologists, who are divided into two schools of mono- 

 genists and polygenists. Those who do not admit the 

 principle of evolution, must look at species either as sep- 

 arate creations or as in some manner distinct entities; 

 and they must decide what forms to rank as species by 

 the analogy of other organic beings which are commonly 

 thus received. But it is a hopeless endeavor to decide 

 this point on sound grounds, until some definition of the 

 term " species " is generally accepted ; and the definition 

 must not include an element which cannot possibly be as- 

 certained, such as an act of creation. We might as well 

 attempt without any definition to decide whether a cer- 

 tain number of houses should be called a village, or town, 

 or city. We have a practical illustration of the difficulty 

 in the never-ending doubts whether many closely-allied 

 mammals, birds, insects, and plants, which represent each 

 other in North America and Europe, should be ranked 

 species or geographical races ; and so it is with the pro- 

 ductions of many islands situated at some little distance 

 from the nearest continent. 



Those naturalists, on the other hand, who admit the 

 principle of evolution, and this is now admitted by the 

 greater number of rising men, will feel no doubt that all 

 the races of man are descended from a single primitive 

 stock ; whether or not they think fit to designate them as 

 distinct species, for the sake of expressing their amount 



19 ' Origin of Species,' 5th edit. p. 68. 



