PREFACE TO THE FIRST EDITION. 7 
trivial appear those causes which it has been pleased to leave dependent on the will of 
man ! How astonishing to behold so many line minds, consuming themselves, so 
uselessly for their own happiness and that of others, in the pursuit of vain combina- 
tions, the very traces of which a few years suffice to obliterate ! 
I avow it proudly, these ideas have been always present to my mind, — the companions 
of my labours ; and if I have endeavoured by every means in my power to advance 
this peaceful study, it is because, in my opinion, it is more capable than any other of 
supplying that want of occupation, which has so largely contributed to the troubles of 
our age ; — but I must return to my subject. 
There yet remains the task of accounting for the principal changes I have effected 
in the latest received methods, and to acknowledge the amiount of obligation to those 
naturalists, whose works have furnished or suggested a part of them. 
To anticipate a remark which will naturally occur to many, I must observe that I 
have neither pretended nor desired to class animals so as to form a single line, or 
as to mark their relative superiority. I even consider every attempt of this kind im- 
practicable. Thus, I do not mean that the mammalia or birds which come last, are 
the most imperfect of their class ; still less do I intend that the last of mammalia 
are more perfect than the first of birds, or the last of mollusks more perfect than the 
first of the annelides, or zoophytes ; even restricting the meaning of this vague word 
perfect to that of “ most completely organized.” I regard my divisions and subdivisions 
as the merely graduated expression of the resemblance of the beings which enter into 
each of them ; and although in some we observe a sort of passage or gradation from 
one species into another, which cannot be denied, this disposition is far from being 
general. The pretended chain of beings, as applied to the whole creation, is but an 
erroneous application of those partial observations, which are only true when confined 
to the limits within which they were made; and, in my opinion, it has proved more 
detrimental to the progress of natural history in modern times, than is easy to 
imagine. 
It is in conformity with these views, that I have established my four principal 
divisions, which have already been made known in a separate memoir. I still think 
that it expresses the real relations of animals more exactly than the old arrangement of I 
Vertehrata and Invertehrata, for the simple reason, that the former animals have a much 
greater mutual resemblance than the latter, and that it was necessary to mark this 
difference in the extent of their relations. 
M. Virey, in an article of the Nouveau Dictionnaire d’Histoire Naturelle, had 
already discerned in part the basis of the division, and principally that which reposes 
on the nervous system. 
The particular approximation of oviparous Vertebrata, inter se, originated from the 
curious observations of M. Geoffroy on the composition of bony heads, and from those 
which I have added to them relative to the rest of the skeleton, and to the muscles. 
In the class of Mammalia, I have brought back the Solipedes to the Pachjdermata, 
and have divided the latter into families on a new plan ; the Ruminantia I have placed 
at the end of the quadrupeds ; and the Manati near the Cetacea. The distribution of 
the Carnaria I have somewhat altered ; the Oustitis have been wholly separated from 
the Monkeys, and a sort of parallelism indicated between the Marsupiata and other 
digitated quadrupeds, the whole from my own anatomical researches. All that I have 
