212 THEORY OF THE CELLS. 
bodies capable of imbibition could be brought to crystallize. 
So long as the object of such a comparison were merely to 
render the representation of the process by which cells are 
formed more clear, there could not be much urged against it ; 
it involves nothing hypothetical, since it contains no explana- 
tion ; no assertion is made that the fundamental power of the 
cells really has something in common with the power by which 
crystals are formed. We have, indeed, compared the growth 
of organisms with crystallization, in so far as in both cases 
solid substances are deposited from a fluid, but we have not 
therefore asserted the identity of the fundamental powers. So 
far we have not advanced beyond the data, beyond a certain 
simple mode of representing the facts. 
The question is, however, whether the exact accordance of 
the phenomena would not authorize us to go further. If the 
formation and growth of the elementary particles of organisms 
have nothing more in common with crystallization than merely 
the deposition of solid substances from out of a fluid, there is 
certainly no reason for assuming any more intimate connexion 
of the two processes. But we have seen, first, that the laws 
which regulate the deposition of the molecules forming the 
elementary particles of organisms are the same for all ele- 
mentary parts; that there is a common principle in the deve- 
lopment of all elementary parts, namely, that of the formation 
of cells; it was then shown that the power which induced the 
attachment of the new molecules did not reside in the entire 
organism, but in the separate elementary particles (this we 
called the plastic power of the cells); lastly, it was shown that 
the laws, according to which the new molecules combine to 
form cells, are (so far as our incomplete knowledge of the laws 
of crystallization admits of our anticipating their probability) 
the same as those by which substances capable of imbibition 
would crystallize. Now the celis do, in fact, consist only of 
material capable of imbibition ; should we not then be justi- 
fied in putting forth the proposition, that the formation of the 
elementary parts of organisms is nothing but a crystallization 
of substance capable of imbibition, and the organism nothing 
but an aggregate of such crystals capable of imbibition ? 
To advance so important a point as absolutely true, would 
certainly need the clearest proof; but it cannot be said that 
