418 Systems of Botany. 



when the spirit of analysis is in full action, and when they are 

 pursuing the intimate knowledge of nature's laws of organiza- 

 tion, through those principles of affinity, by improved optics and 

 improved reasoning. To that natural system of considering or- 

 ganized beings, which is founded upon observation of the agree- 

 ment of a particular animal or plant, to all other animals and 

 plants, man has made but slow advances, owing to the human 

 mind, at its most active periods, having been principally engaged 

 in speculative inquiries, and to the general ignorance of com- 

 parative anatomy, both animal and vegetable. It is true, men, 

 at an eai-ly period, might discover that there was a very wide 

 difference among the animals they called fishes, since a whale, 

 which dwells in the water, and has — the tail fin excepted — the 

 external form of a fish, respires by lungs as we do, and not by 

 gills ; brings its young alive into the world, and suckles it. The 

 bat also, although it flies in the air, and at a distance is an ap- 

 parent bird, has no feathers, but is a true quadruped, with 

 claws to its winged fore feet, as well as its hind feet, has ears, 

 brings forth its young alive, and suckles it from teats at its breast. 

 Hence, it being perceived that some animals belonging to the 

 water and the air, had important functions in common with 

 many living on the earth, it was a simple step to class them to- 

 gether ; and thus the class mammalia, to which man belongs, 

 was established, and placed at the head of the animal kingdom, 

 as that class of animals, whether living on the earth, in the wa- 

 ters, or flying in the air, which suckles its young. A classification 

 in zoology, which subtracts from the mass of animals all those 

 which have an undoubted affinity of character, tending to the 

 same functions, and then subdivides these classes again upon the 

 same principles, promises an arrangement of all animals accord- 

 ing to their affinities ; for those thus closely resembling each other, 

 would come to be arranged under the same species ; species re- 

 sembling each other under the same genus ; genera resembling 

 each other under the same order : and a catalogue of animals 

 thus arranged, would be a true system of animal nature ; for 

 the classification, in disclosing the structure of each animal, 

 would explain the purposes in creation, for which it received its 

 distinctive properties. 



To effect so true an arrangement of organic nature, — for 

 what is said here of animals, will be found equally true of vege- 



