INTRODUCTION. 5 



true fundamental distinctions, on the essential resemblances of beings, 

 that method is the surest means of reducing the properties of beings to 

 general rules, of expressing them in the fewest words, and of stamping 

 them on the memory. 



To render it such, we employ an assiduous comparison of beings, 

 directed by the principle of subordination of character, which is itself 

 derived from that of the conditions of existence. As every being 

 possesses a mutual adaptation of parts necessary to its mode of existence, 

 some traits of conformation entirely preclude characters which, on the 

 contrary, are necessary in others. When, therefore, we perceive such 

 or such traits in a being, we can calculate beforehand those that co-exist 

 in it, or others that may be incompatible with them. The parts, the 

 properties, or the traits of conformation, \vhich 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 called the important or dominating characters ; the 

 others are the subordinate characters, all varying in degree. 



This influence of character is sometimes determined rationally, by 

 the consideration of the nature of the organ. When this is impracti- 

 cable, we have recourse to simple observation ; and a sure mark by 

 which we may recognise the important characters, and one which is 

 drawn from their own nature, is the superior constancy they exhibit, 

 so that in a long series of different beings, approximating according to 

 their degrees of similitude, these characters are the last to vary. That 

 such characters should be preferred for distinguishing the great divisions, 

 and that in proportion as we descend to the inferior subdivisions, we 

 can also descend to subordinate and variable characters, is a rule result- 

 ing equally from their influence and constancy. 



There can be but one perfect method, which is the natural method. 

 We thus name an arrangement in which beings of the same genus are 

 placed nearer to each other than to those of the other genera; the 

 > genera of the same order nearer than those of the other orders, and soon. 

 This method is the ideal to which Natural History should tend ; for it 

 is evident that if we can reach it, we shall have the exact and complete 

 expression of all nature. In fact, each being is determined by its 

 resemblance to others, and difference from them ; and all these relations 

 would be fully given by the arrangement in question. In a word, the 

 natural method would be the whole science, and every 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 in all ages 



