54 THE HISTORY OF CREATION. 
arrived at the same conclusion by means of comparative 
anatomy, recognized the true cause of this difference. 
This is disclosed to us by the Theory of Descent. The 
wonderful and astonishing similarity in the inner organ- 
ization and in the anatomical relations of structure, and 
the still more remarkable agreement in the embryonic de- 
velopment of all animals belonging to one and the same 
type (for example, to the branch of the Vertebrate animals), 
is explained in the simplest manner by the supposition of 
their common descent from a single primary original form. 
If this view is not accepted, then the complete agreement of 
the most different Vertebrate animals, in their inner struc- 
ture and their manner of development, remains perfectly 
inexplicable. In fact it can only be explained by the law of 
inheritance. 
Next to the comparative anatomy of animals and the 
systematic zoology founded anew by it, it was specially to 
the science of petrifactions, or Paleontology, that Cuvier 
rendered great service. We must draw special attention 
to this, because these very paleontological views, and the 
geological ideas connected with them, were held almost 
universally in the highest esteem during the first half of 
the present century, and caused the greatest hindrance to 
the working out of a truly natural history of creation. 
Petrifactions, the scientific study of which Cuvier pro- 
moted at the beginning of our century in a most ex- 
tensive manner, and established quite anew for the Verte- 
brate animals, play one of the most important parts in the 
“non-miraculous history of creation.” For these remains 
and impressions of extinct animals and plants, preserved to 
us in a petrified condition, are the true “monuments of the 
