120 THE HISTORY OF CREATION. 
All the naturalists and philosophers with whom we have 
become acquainted in this brief historical survey, as men 
adopting the Theory of Development, merely arrived at the 
conception that all the different species of animals and 
plants which at any time have lived, and still live, upon 
the earth, are the gradually changed and transformed de- 
scendants of one or some few original and very simple 
prototypes, which latter arose out of inorganic matter by 
spontaneous generation. But none of them succeeded in 
placing this fundamental element ‘of the doctrine of descent 
in relation with some cause, nor in satisfactorily explaining 
the transformation of organic species by the true demonstra- 
tion of its mechanical antecedents. Charles Darwin was 
the first who solved this most difficult problem, and this 
forms the broad gulf which separates him from his pre- 
decessors. 
The special merit of Charles Darwin is, in my opinion, 
twofold: in the first place, the doctrine of descent, the 
fundamental idea of which was already clearly expressed by 
Goethe and Lamarck, has been developed by him much 
more comprehensively, has been traced much more minutely 
in all directions, and carried out much more strictly and 
connectedly than by any of his predecessors; and secondly, 
he has established a new theory, which reveals to us the 
natural causes of organic development, the acting causes 
(cause efficientes) of organic form-production, and of the 
changes and transformations of animal and vegetable species. 
This is the theory which we call the Theory of Selection, or 
more accurately, the Theory of Natural Selection (selectio 
naturalis). 
When we reflect that (with the few exceptions above men- 
