AGASSIZ ON CREATION, 63 
and vary within certain narrow limits; never in essential 
qualities, but only in unessential points. No new species 
could ever proceed from the changes or varieties of a species. 
Not one of all organic species, therefore, is ever derived from 
another, but each individual species has been separately 
created by God. Each individual species, as Agassiz 
expresses it, is “an embodied creative thought ” of God. 
In direct opposition to the fact established by palzeonto- 
logical experience, that the duration of the individual 
organic species is most unequal, and that many species 
continue unchanged through several successive periods of 
the earth’s history, while others only existed during a small 
portion of such a period, Agassiz maintains that one and 
the same species never occurs in two different periods, but 
that each individual period is characterized by species of 
animals and plants which are quite peculiar, and belong to 
it exclusively. He further shares Cuvier’s opinion that the 
whole of these inhabitants were annihilated by the great 
and universal revolutions of the earth’s surface, which 
divide two successive periods, and that after its destruction 
a new and specifically different assemblage of organisms was 
created. This new creation Agassiz supposes to have taken 
place in this manner: viz, that at each creation all the 
inhabitants of the earth, in their full average number of 
individuals, and in the peculiar relations corresponding 
to the economy of nature, were, as a whole, suddenly placed 
upon the earth by the Creator. In saying this he puts 
himself in opposition to one of the most firmly established 
and most important laws of animal and vegetable geography 
—namely, to the law that each species has a single original 
locality of origin, or a so-called “centre of creation,” from 
