PROGRESS OF SYSTEMATIC ZOOLOGY. 



parts of our history, that not only labor but time, not only one man 

 of genius but several, and those succeeding each other, are requisite 

 to the formation of any considerable science. 



But, in reality, the statements to which we refer, respecting the 

 scientific character of Aristotle's Zoological system, are altogether 

 without foundation ; and this science confirms the lessons taught us by 

 all the others. The misstatements respecting Aristotle's doctrines are 

 on this account so important, and are so curious in themselves, that I 

 must dwell upon them a little. 



Aristotle's nine Books On Animals are a work enumerating the 

 differences of animals in almost all conceivable respects ; in the 

 organs of sense, of motion, of nutrition, the interior anatomy, the 

 exterior covering, the manner of life, growth, generation, and many 

 other circumstances. These differences are very philosophically esti- 

 mated. " The corresponding parts of animals," he says, 1 " besides the 

 differences of quality and circumstance, differ in being more or fewer, 

 greater or smaller, and, speaking generally, in excess and defect. 

 Thus some animals have crustaceous coverings, others hard shells ; some 

 have long beaks, some short ; some have many wings, some have few ; 

 Some again have parts which others want, as crests and spurs." He 

 then makes the following important remark : " Some animals have 

 parts which correspond to those of others, not as being the same in 

 species, nor by excess and defect, but by analogy ; thus a claw is ana- 

 logous to a thorn, and a nail to a hoof, and a hand to the nipper of a 

 lobster, and a feather to a scale ; for what a feather is in a bird, that 

 is a scale in a fish." 



It will not, however, be necessary, in order to understand Aristotlr 

 for our present purpose, that we should discuss his notion of Analogy. 

 He. proceeds to state his object, 2 which is, as we have said, to describe 

 the differences of animals in their structure and habits. He then 

 observes, that for structure, we may take Man for our type, 3 as being 

 best known to us ; and the remainder of the first Book is occupied 

 with a description of man's body, beginning from the head, and pro- 

 ceeding to the extremities. 



In the next Book, (from which are taken the principal passages in 

 which his modern commentators detect his system,) he proceeds to 

 compare the differences of parts in different animals, according to the 

 order which he had observed in man. In the first chapter he speaks 



1 Lib. i. c, L * Lib. i. c. ii. 8 c. iii 



