354 THE HISTORY OF CREATION. 



the heights of mountains and in the depths of the ocean, 

 but especially the important phenomenon that every species 

 of organism proceeds from a so-called " centre of creation " 

 (more correctly a " priniceval homie" or "centre of distribu- 

 tion ") ; that is, from a single locality, where it originated 

 but once, and whence it spread. 



(9.) The oecology of organisms, the knowledge of the sum 

 of the relations of organisms to the surrounding outer 

 %vorld, to organic and inorganic conditions of existence ; the 

 so-called " economy of nature," the correlations between all 

 organisms living together in one and the same locality, their 

 adaptation to their surroundings, their modification in the 

 struggle for existence, especially the circumstances of para- 

 sitism, etc. It is just these phenomena in " the economy of 

 nature " which the unscientific, on a superficial consideration, 

 are wont to regard as the wise arrangements of a Creator 

 acting for a definite purpose, but which on a more attentive 

 examination show themselves to be the necessary results of 

 mechanical causes. 



(10.) The unity of Biology as a whole, the deep inner con- 

 nection existing between all the phenomena named and all 

 the other phenomena belonging to zoology, protistics, and 

 botany, and which are simply and naturally explained by a 

 single common principle. This principle can be no other 

 than the common derivation of all the specifically different 

 organisms from a single, or from several absolutely simple, 

 primary forms like the Monera, which possess no organs. 

 The Theory of Descent, by assuming this common deriva- 

 tion, throws a clear light upon these individual series of 

 phenomena, as well as upon their totality, without which 

 their deeper causal connection would remain completely 



