zViil PREFACE TO THE FIRST EDITION. 
first remarks on organization—to employ them in order to arrive at new 
ones, and to render the distribution perfect—in fine, from this mutual re- 
action of the two sciences, to elicit a system of zoology that might serve 
as an introduction and a guide in anatomical investigations, and as a body 
of anatomical doctrine fitted to develope and explain the zoological system. 
The first results of this double labour appeared in 1795, in a special 
memoir upon a new division of the white-blooded animals. A sketch of 
their application to genera, and to their division in subgenera, was the 
object of my elementary “ Tableau Elémentaire des Animaux,” printed 
in 1798, which, in conjunction with M. Dumeril, I improved, in the tables 
annexed to the first volumes of my “ Legons d’Anatomie Comparée” in 
1800. 
I should, perhaps, have contented myself with perfecting these tables, 
and proceeded immediately to the publication of my great work on ana- 
tomy, if, in the course of my researches, I had not been frequently struck 
with another defect of the greater number of the general or partial sys- 
tems of zoology; I mean the confusion in which the want of critical 
acumen has left a great number of species, and even several genera. 
Not only were the classes and orders not in conformity with the in- 
timate nature of the animals, for the purpose of forming a foundation for 
a treatise on comparative anatomy; but the genera, though undoubtedly 
for the most part better composed, presented in their nomenclature very 
inadequate materials, inasmuch as the species were not arranged under each 
of them respectively according to its character. Thus, in placing the Sea- 
cow (Manatus, Cuv.) in the genus Morse (Trichechus, Lin.), the Siren in 
that of the Eels, Gmelin had rendered any general proposition relative to 
the organization of these two genera impossible, just as by approximating 
to the same class the same order, and placing side by side the Sepia and 
the fresh water Polypus, he had made it impossible to say any thing in 
general on the class and order which embraced such different beings. 
The examples above cited are selected from the most striking of these 
errors; but the number of them that existed was infinite, and, though 
not so easily to be perceived at the first glance, still they were not the 
less sources of real inconvenience. 
It was not enough, then, to have imagined a new arrangement of classes 
and orders, and to have properly placed the genera there; it was also ne- 
cessary to examine all the species, in order to ascertain if they really be- 
longed to the genera in which they had been placed. 
When I came to do this, I not only found that the species were either 
grouped or distributed in defiance of common sense; but I saw that many 
of the species were by no means positively established by the characters 
attributed to them, or by the figures and descriptions given of them. 
