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nization is submitted to the same law... . . . It cannot be said that 
any one of the domestic animals, in its most extreme varieties, loses 
the character of the species. . : 
“The science of geology is not yet in a condition to give a satis- 
factory answer to many difficulties that may arise in the theory of 
successive creations ; and though we may with greater or less distinct- 
ness foresee such a solution, it cannot yet be demonstrated. A strict 
and intelligent study of nature is required, in order to bring together 
the various materials. We must know better than we do now each one 
of the successive creations, in order to form a complete idea of their 
mutual relations, and of their differences from those which have pre- 
ceded and followed them. This is the most important problem of 
paleontology, and its solution is only to be found in the observation 
of facts, for they alone are permanent, and they perhaps will outlive 
all the theories discussed at the present day.”’ 
Di, quibus imperium est animarum, umbreque silentes, 
Et Chaos, et Phlegethon, loca nocte silentia late ; 
Sit mihi fas audita loqui: sit numine vestro 
Pandere res alta terra et caligine mersas. 
