RISE AND PROGRESS OF ZOOLOGY. 85 
internal anatomy? why call in the aid of another 
science to make that object more perfectly known, 
which was before sufficiently plain for all the purposes 
of recognition? If, as it has been asserted, natural 
arrangement depends upon internal anatomy, how do 
we know that it is not equally dependent upon che- 
mistry ? Has this theory led to the discovery of the 
natural system? or to any one of those laws by which 
such a system may be supposed to be regulated ? — 
- Certainly not. The law, as it has been termed, of 
the condition of existence*, is no more than that 
every animal is constructed according to the func- 
tions it is destined by nature to perform. Now, so 
far from this, as some have insinuated, being a 
modern discovery, it was well known to Aristotle ; 
and is a truth apparent to the most superficial ob- 
server. It must be admitted, however, that M. Cuvier 
is the only one of this school who has attached 
to this theoretic principle of internal organisation 
so much undue importance: an error he was ob- 
viously led into from the splendid success which 
attended its use in his researches on the fossil 
bones; where, indeed, a complete knowledge of 
comparative anatomy was absolutely indispensable. 
It is not maintained that a knowledge of internal 
anatomy is superfluous to the zoologist ; but that it 
is quite redundant (and therefore unnecessary), 
where all that is essential to be Known of an animal 
can be learned from external organisation. With 
the exception, therefore, of M. Cuvier, the systems 
of his celebrated cotemporaries may be said to make 
* Régne Animal, 
G 3 
