INORGANIC EVOLUTION 15 



formation of the earth, the sun and all astronomical 

 bodies has been studied with eminent success by as- 

 tronomers. Both the nebular and planetesimal hy- 

 potheses are reasonable and acceptable. The study of 

 geology has made great progress. But biology, or the 

 science of life, on the earth, is that part of evolution 

 which lies the closest to man, and therefore interests him 

 more than all others. The immense number of species, 

 or life forms, each being characterized differently from 

 other forms, and each being descended from common an- 

 cestors, in both the vegetable and animal kingdom, pre- 

 sented to the intellect of man a most profound and 

 important study. 



ORIGIN OF SPECIES. For the last fifty years the in- 

 tellectual world has been wonderfully agitated upon 

 the origin of these species. The great majority of inves- 

 tigators and writers had, prior to the publication of the 

 "Origin of Species" by Darwin in 1859, looked upon 

 species, as specially created, as stated in Genesis, with 

 immutable differences, impassable by any natural pro- 

 cess. In the light of the proofs given by Darwin, of their 

 actual mutability, and these facts, especially that of ex- 

 periments in breeding, in domestication, having been 

 familiar to the farmer, the botanist, and the breeders of 

 food animals, it is astonishing, that others did not see 

 the bearing of the facts, in the same way Darwin did. 

 Darwin's theory is, that all species vegetable and animal 

 have originated by variations from the forms of their 

 parents, in the anatomy and physiology of the offspring, 

 which variations, making them better adapted to the en- 

 vironment, and to spread over a larger area for food, 

 were continued and increased by heredity. In this way 

 all species have arisen from a lowly form, whose origin 

 Darwin does not discuss. The theory and its proof are 

 discussed in future pages of this volume. 



