XIV PREFACE. 
the different organs of animals, and determine the 
functions which are executed, previous to the syste- 
matical arrangement of the species, than to unfold 
the peculiarities of the various organs as they occur 
in succession in the different classes. By this me- 
thod, the student is made acquainted with the va- 
rieties of organization and function, and proceeds 
to the details of methodical distribution, with his 
mind prepared by general views for conducting the 
particular investigations. In the distribution of the 
various groups, the author, after the plan of the 
“ Regne Animal” of M. Cuvier, the most valua- 
ble of modern systematical arrangements, begins 
with the perfect animals, and terminates with 
those which exhibit the most simple organisation. 
Suppose an opposite plan to be pursued, many diffi- 
culties must present themselves in the course of the 
arrangement. As the observer ascends in the scale, 
new organs develope themselves. These are at first 
so obscure, that he can neither unfold their structure 
nor guess at their functions, without being guided 
by his knowledge of the organs of the higher tribes : 
hence it happens, that the boasted analytical me- 
thod becomes, in fact, synthetical; and the very 
terms which are employed to express the characters 
intimate a knowledge of the peculiarities of the high- 
er divisions. 
