74 
MODERN SYSTEM. 
ON THE 
DIVISION of ANIMALS from their ORGANIZATION. 
It is the object of comparative anatomy to point out the difference 
which each organ presents when considered in every animal : but this 
exposition would prove very tedious and intricate, were we obliged at 
every step to enumerate all the animals in which particular organs ha' c 
a uniform structure. It is certainly much more convenient to indicate 
them all at once under the name of a class or genus which may com- 
prehend the whole; but to enable us to form this arrangement, it is ne- 
cessary that all the animals which compose a genus or a class, should 
possess some resemblance not only in one, but in all their organs. 
Nature never oversteps the bounds which the necessary conditions 
of existence prescribe to her ; but whenever she is unconfined by these 
conditions, she displays all her fertility and variety. Never departing 
from the small number of combinations that arc possible between the 
essential modifications of important organs, she seems to sport with in- 
finite caprice in all the accessary parts. In these there appears no ne- 
cessity tor a particular form or disposition. It even frequently happens 
that particular forms and dispositions are created without any apparent 
view to utility. It seems sufficient that they should be possible; that 
is to sav, that they do not destroy the harmony of the whole. 
Among these numerous combinations there arc necessarily many 
which have common parts, and there arc always a certain number 
which exhibit very few differences. By the comparison therefore o 
those which resemble each other, we may establish a kind of series 
which will appear to descend gradually from a primitive type. These 
considerations are the foundations of the ideas from which Certain na- 
turalists have formed a scale of brings, the object of which is to exhibit 
the most perfect, and terminating with the most simple kind of organ- 
ization — with that which possesses the least numerous and most com- 
mon properties ; so that the mind passes from one link of the chain m 
the other, almost without perceiving any interval, and, as it were, by 
insensible shades. _ ... , , 
The object of system is to reduce a science to its simplest terms ; 
< reducing the propositions it comprehends to the greatest degree of g e ' 
neralityof which they are susceptible. A good method in comparative 
anatomy must, therefore, be such as will enable us to assign to euc" 
class and to each of its subdivisions, some qualities common to tt» 
greater part of the organs. This object is to be attained by two cW' 
ferent means, which may serve to prove or verify one another. 1 
first, and that to which all men will naturally have recourse, is to pr° 
cccd from the observations of species to uniting them in genera, a 11 
