75
Moreover, animals of different types, living in the sameelement, have no sort of similarity as to size. The aquaticInsects , the aquatic Mollusks , fall in with the average sizeof their class, as well as the aquatic Reptiles and theaquatic Birds, or the aquatic Mammalia ; but there is nocommon average for either terrestrial or aquatic animalsof different classes taken together. And in this lies theevidence that organized beings are independent of themediums in which they live, as far as their origin is con-cerned, though it is plain that, when created, they weremade to suit the element in which they were placed.
To me these facts show that the phenomena of life aremanifested in the physical world, and not through or byit; that organized beings are made to conquer and assi-milate to themselves the materials of the inorganic world;that they maintain their original characteristics, notwith-standing the unceasing action of physical agents uponthem. And I confess I cannot comprehend how beings soentirely independent of these influences could be producedby them.
SECTION XV.
PERMANENCY OF SPECIFIC PECULIARITIES IN ALL ORGANIZED
BEINGS.
It was a great step in the progress of science when itwas ascertained that species have fixed characters, andthat they do not change in the course of time. But thisfact, for which we are indebted to Cuvier , 1 has acquired astill greater importance since it has also been established,that even the most extraordinary changes in the mode ofexistence, and in the conditions under which animals
1 Cuvier (Or.), Recherches sur les Paris, 1821, 5 vols., 4to., fig. vol. i,ossements fossiles, etc., Nouv. 6dit.; sur l’lbis, p. cxli.