326 CLASSIFICATION OF ANIMALS. 



if they did not exhibit remarkable differences which render it easy 

 to establish distinctions among them. Hence zoologists have al- 

 ways been attentive to these differences, and by dividing animals 

 accordingly, either into more or fewer classes, have conveniently 

 formed what are called methods. It is certain, indeed, that no such 

 classifications exist in nature, where all the various individuals con- 

 stitute one continued and uninterrupted chain; yet they considera- 

 bly assist the memory, and may be rendered truly useful guides in 

 the study of animated being. Methods are, therefore, to be consi- 

 dered as instruments suited to our weakness, which may be benefi- 

 cially resorted to, in tracing the wide field over which the stores of 

 nature lie strewed in an immeasurable harvest. 



The divisions which Aristotle adopted were very general and 

 simple, being chiefly taken from the external characters of form, 

 food, habit, or habitation : he did not, indeed, conceive that in his 

 age zoology was sufficiently advanced for any thing of comprehen- 

 sive or methodical arrangement ; but he was sufficiently sensible of 

 its advantages, and strongly recommended to succeeding naturalists 

 a minute attention to the internal as well as the external organs of 

 animals ; and it is upon this recommendation that most of the sys- 

 tems of modern times have been founded ; as those of Gesner, Al- 

 drovandi, Ray, Johnston, Charleton, Klein, Linnaeus, Artedi, Brisson, 

 Daubenton, Geoffroy, Cuvier, and Blumenbach : all of whom have 

 flourished since the middle of the sixteenth century ; most of whom 

 have contributed something of importance to a scientific method of 

 studying and distributing animals; and the most celebrated of whom 

 are Ray, Linnaeus, Cuvier, and Blumenbach. 



The system of Ray is derived in its outlines from the recommend- 

 ation of Aristotle, to attend to the different structures of different 

 descriptions of animal life ; and his observation that one of these 

 differences consists in their possessing lungs and a sanguineous sys- 

 T tern, or their being destitute of lungs and exsanguineous. The 

 j Linnasan method is, for the most part, built upon this general 

 ^ arrangement of Mr. Ray, especially in regard to quadrupeds : it is, 

 rt however, an extension of it, and certainly an improvement. That 

 a of M. Cuvier, in its subordinate divisions is founded upon both 

 J these; but, in its primary aud leading distinctions, upon the nervous 

 * or sensorial, instead of upon the respiratory and sanguineous sys- 

 j terns ;all animals being, upon M. Cuvier s scheme, divided into 



