10 DARWINISM CHAP. 



Species should be carefully considered. It is as follows : 

 "Although much remains obscure, and ■will long remain 

 obscure, I can entertain no doubt, after the most deliberate 

 and dispassionate judgment of which I am capable, that the 

 view which most natiu-alists until recently entertained and 

 which I formerly entertained — namely, that each species has 

 been independently created — is eiToneous. I am fully con- 

 vinced that species are not immutable ; but that those 

 belonging to what are called the same genera are lineal 

 descendants of some other and generally extinct species, in 

 the same manner as the acknowledged varieties of any one 

 species are the descendants of that species. Furthermore, I 

 am convinced that Natural Selection has been the most im- 

 portant, but not the exclusive, means of modification." * 



It should be especially noted that all which is here claimed 

 is now almost universally admitted, while the criticisms of 

 Darwin's works refer almost exclusively to those numerous 

 questions which, as he himself says, " will long remain 

 obscure." 



The Darwinian Tlieory. 



As it \\\\\ be necessary, in the follo"vving chapters, to set 

 forth a considerable body of facts in almost every department 

 of natural history, in order to establish the fundamental 

 propositions on which the theory of natural selection rests, 

 I propose to give a preliminary statement of what the theory 

 really is, in order that the reader may better appreciate the 

 necessity for discussing so many details, and may thus feel a 

 more enlightened interest in them. Many of the facts to be 

 adduced are so novel and so curious that they are sure to be 

 appreciated by every one who takes an interest in nature, but 

 unless the need of them is clearly seen it may be thought that 

 time is being wasted on mere curious details and stranire facts 

 which have little bearing on the question at issue. 



The theory of natural selection rests on two main classes 

 of facts which apply to all organised beings without exception, 

 and Avhich thus take rank as fundamental principles or laws. 

 The first is, the power of rapid multiplication in a geometrical 

 progression ; the second, that the offspring always vary slightly 

 from the parents, though generally very closely resembling 



