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 “primeval home,” or “centre of distribu- 
tion”); that is, from a single locality, where it originated 
but once, and whence it spread. 
 (9.) The ecology of organisms, the knowledge of the sum 
of the relations of organisms to the surrounding outer 
world, to organic and inorganic conditions of existence; the 
so-called “ economy of nature,” the correlations between ail 
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, ete. 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 
