190 ZOOLOGY. 



important modifications without affecting others, whilst there 

 are others which, when modified strongly, affect the character 

 of the ivst. These may be called dominating organs. 15y 

 these organs the anatomist, and in some measure the naturalist, 

 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.* 



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 men 

 that he gives to his parent, yet he does not confound the indi- 

 viduals; and, in a word, it may be said that this tendency to 

 classify extends throughout the whole range of our intel- 

 lectuality. 



This necessity to reunite in our minds similar objects, and 

 to give to each of the groups thus formed an ideal repre- 

 sentative, is in fact the basis of all classification, and its 



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

 tion <J la Zoo/o,/ ..r, Considerations on the Tendencies of Nature 

 in the Constitution of the Animal Kingdom. 



