CHAPTEK II. 



IMPORTANCE OF THE CONSIDERATION OF AFFINITIES. 



Among living bodies the name affinity has been given to features of 

 analogy or resemblance between two objects, that are compared in 

 their totality, but with special stress on the most essential parts. 

 The closer and more extensive the resemblance, the greater the 

 affinities. They indicate a sort of kinship between the living bodies 

 which exhibit them ; and oblige us in our classification to place 

 these bodies in a proximity proportional to their affinities. 



How great has been the progress of natural science since serious 

 attention began to be given to affinities, and especially since their 

 true underlying principles have been determined ! 



Before this change, our botanical classifications were entirely at 

 the mercy of arbitrary opinion, and of artificial systems of any 

 author. In the animal kingdom the invertebrate animals comprising 

 the larger part of all known animals were classified into the most 

 heterogeneous groups, some under the name of insects, some under the 

 name of worms ; where the animals included are from the point of 

 view of affinity widely different from one another. 



Happily this state of affairs is now changed ; and, henceforth, if 

 the study of natural history is continued, its progress is assured. 



The principle of natural affinities removes all arbitrariness from 

 our attempts at a methodical classification of organised bodies. We 

 have here the law of nature which should guide us to the natural 

 method. Naturalists are forced to agree as to the rank which they 

 assign, firstly to the main groups of their classification, and after- 

 wards to the individuals of which these groups are composed ; finally, 

 they are obliged to follow the actual order observed by nature in 

 giving birth to her productions. 



Thus, everything that concerns the affinities of the various animals 

 should be the chief object of our researches, before making any division 

 or classification among them. 



