6 The Rev. V. Keith on the Structure of Animals, 



penetrating eye. The result was that his arrangements in 

 zoology were adopted and applauded with the same eagerness 

 and universality as his arrangements in botany. He distri- 

 butes animals into six classes, — mammalia, birds, amphibia, 

 fishes, worms, insects*. It was a great improvement upon 

 preceding arrangements, but still it is liable to many objec- 

 tions. Under the honourable and imposing title o^ Primates^ 

 — the nobles of the creation, — it groups together men, mon- 

 keys, and bats, in the same class and in the same order; while 

 it exhibits other incongruities equall}' palpable. But from 

 arrangements founded upon the number of teeth, or of toes, 

 what was to be expected but unnatural associations ? It should 

 be recollected, however, that his arrangements are professedly 

 artificial, and are not to be tried by such rules of criticism as 

 are applicable to arrangements professing to be natural. They 

 have been reformed and improved by Blumenbach -j-, as far, 

 perhaps, as they are capable of improvement; and in their 

 present improved state they may be regarded as making a 

 laudable approximation to the arrangements of nature. The 

 characters of the classes are taken partly from the external 

 structure, and partly from the internal structure. But Cuvier 

 in his Regne Animal, and Carus in his Introduction to the 

 Comparative Anatomy of Animals, have established a new 

 principle of arrangement, and have shown to the satisfaction 

 of zoologists, that all characters of classes truly natural must 

 be taken from the internal structure only, as exhibiting most 

 distinctly the several grades, or several degrees of excellence, 

 that exist among animals, whether as relative to sensation or 

 to locomotion — the very essence of animal ity, and measure of 

 animal perfection. This view may be taken in the order, 

 either of the ascending or of the descending scale, according 

 to the peculiar object of the investigator. Carus adopts the 

 first of the two modes, and ascends from the lowest and mi- 

 nutest animalcule up to man. Cuvier adopts the second of 

 the two modes, and descends from man down to the meanest 

 entity endowed with animal life. His leading and primary 

 divisions, now universally [?] adopted, are the four following |. 



The first and highest division of the animal scale includes 

 man, and the animals resembling him most nearly in the form 

 and complexity of their internal structure. The leading cha- 

 racter on which it is founded is, that the brain, and the chief 

 trunk of the nervous system, are inclosed in bony coverings 

 the former in the cranium, the latter in the vertehrce, or [joints 

 composing the] back-bone, to the sides of which the ribs, and 

 the bones composing the limbs, which are never more than 



• Systenm Natura:, 1735. f Manual of Nat. Hist., R. T. Gore. 



X liegne Animal^ Introcl. 



