200 ZOOLOGY. 



made with safety the basis of a priori reasoning. K. K. See 

 "Trans. Boy. Soc. of Edin.," 1829.] 



357. In studying this law of organic harmony, we 

 soon discover another, the subordination of characters. It 

 becomes evident that all parts of the animal economy have 

 not the same importance ; that certain organs may undergo 

 important modifications without affecting others, whilst there 

 are others which, when modified strongly, affect the character 

 of the rest. These may be called dominating organs. By 

 these organs the anatomist, and in some measure the natu- 

 ralist, must be regulated in his determinations. By the 

 fixity or mobility of an organ he determines its importance 

 in the economy. 



358. There are other principles regulating the great 

 work of creation, on which want of space forbids us to dwell. 

 The tendency, for example, to repetition, which leads to the 

 formation of homologous parts ;* the principle of connexion of 

 organs regulating the place occupied by each ; a tendency to 

 an organic balancement, equipoise, or compensation, when the 

 development of an organ acts as it were injuriously upon 

 others, as if the amount of vital force were restricted and 

 limited. All these subjects merit consideration, but space is 

 wanting to do them justice. Sufficient has been said to show 

 that nature proceeds always by rule and measure ; and that 

 the animal kingdom, so far from being a confused assemblage 

 of ill-assorted beings, unfolds itself to the eyes of the observer 

 as a vast picture, where all harmonizes and is linked together ; 

 finally, that the zoological laws are as simple as they are 

 general.f 



ZOOLOGICAL CLASSIFICATIONS. 



359. Object and Nature of Zoological Classifications. 

 Man naturally groups the various objects around him, and 

 he gives to these groups a different name. This tendency to 

 classification is one of the most remarkable of our faculties, 

 and powerfully aids in facilitating the operations of the mind ; 

 by its means we rise from the individual to the general, and 

 thus form generalizations and abstract ideas. It is seen in 

 infancy, for the child gives instinctively the same name to all 



* The term homologne is with some reserved exclusively for parts 

 strictly representing each other in different animals. E. K. 



f See on this subject a work I have published, under the title of Introduc- 

 tion a la Zoologie Generate, or, Considerations on the Tendencies of Nature 

 in the Constitution of the Animal Kingdom. 



