INTRODUCTION. 
16 
called a method. It is, in some respects, a sort of dictionary, in which we proceed ^ 
from the properties of things to discover their names ; being the reverse of ordinary die- | 
tionaries, in which we proceed from the names to obtain a knowledge of the properties. 
When the method, however, is good, it does more than teach us names. If the sub- 
divisions have not been established arbitrarily, but are based on the true fundamental ^ 
relations, — on the essential resemblances of beings, the method is the surest means of 1 1 
reducing the properties of these beings to general rules, of expressing them in the | j 
fewest words, and of stamping them on the memory. 1m 
To render it such, an assiduous comparison of beings is employed, directed by the IJ 
principle of the subordination of characters, which is itself derived from that of the Ijl 
conditions of existence. All the parts of a being having a mutual correlativeness, some Ijj 
traits of conformation exclude others ; while some, on the contrary, necessitate others : j - 
when, therefore, we perceive such or such traits in a being, we can calculate before- ;! 
hand those which co-exist in it, or those that are incompatible with them. The parts, i 
properties, or the traits of conformation, which have the greatest number of these | | 
relations of incompatibility or of co-existence with others, or, in other words, that ' | 
exercise the most marked influence upon the whole of the being, are what are called s j 
important characters, dominant characters ; the others are the subordinate characters, ' 
all varying, however, in degree. 
This influence of characters is sometimes determined rationally, by considering 
the nature of the organ : when this is impracticable, recourse must be had to simple 
observation ; and a sure means of recognizing the important characters, which is 
derived from their own nature, is, that they are more constant ; and that in a long 
series of dilFerent beings, approximated according to their degrees of similitude, these 
characters are the last to vary. 
From their influence and from their constancy result equally the rule, which should 
be preferred for distinguishing grand divisions, and in proportion as we descend to the 
inferior subdivisions, we can also descend to subordinate and variable characters. 
There can only be one perfect method, which is the natural method. An arrangement 
is thus named in which beings of the same genus are placed nearer to each other than 
to those of all other genera ; the genera of the same order nearer than to those of 
other orders, and so in succession. This method is the ideal to which Natural History 
should tend ; for it is evident that, if we can attain it, we shall have the exact and 
complete expression of all nature. In fact, each being is determined by its resem- 
blance to others, and its differences from them ; and all these relations would be fuUy 
given by the arrangement which we have indicated. In a word, the natural method would 
be the whole science, and each step towards it tends to advance the science to perfection. 
Life being the most important of all the properties of beings, and the highest of all 
characters, it is not surprising that it has been made in all ages the most general prin- 
ciple of distinction ; and that natural beings have always been separated into two 
immense divisions, the living and the inanimate. 
OF LIVING BEINGS, AND OF ORGANIZATION IN GENERAL. 
If, in order to obtain a just idea of the essence of life, we consider it in those beings 
in which its effects are the most simple, we readily perceive that it consists in the 
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