GENERAL NOTIONS ON NATURAL HISTORY. 21 



These three branches of the natural history of animals and of 

 plants, constitute three sciences which are known under names 

 of Zoology, (or, when plants are referred to, descriptive Botany,) 

 Anatomy, and Pky&HHogy. 



14. ANATOMY treats of the internal conformation of living 

 deinr/s : it studies them by the aid of dissection, and acquaints us 

 with the position, the form, and the structure of their organs. In 

 as much as it embraces the consideration of either animals or 

 plants, it constitutes two distinct sciences : Zoological tfitctomy, 

 and Vegetable. Anatomy. 



15. PHYSIOLOGY is the Science of Life; it teaches the use of 

 different organs, and the manner in which these act, to produce 

 the different phenomena, (that, is, visible qualities), proper to 

 living beings. Like Anatomy, it may have for its domain either 

 the animal or vegetable kingdom, and it is consequently divided 

 into Animal Physiology, and Vegetable Physiology. 



16. It is easy to understand that, without the aid of Anatomy 

 and Physiology, the profound study of natural history would be 

 impossible. When we wish to obtain an exact idea of a watch, 

 we do not limit ourselves to observing its exterior form, and to 

 noticing the manner in which the hands turn ; we open it, we 

 examine every wheel, every chain, every spring : we would 

 separate them one by one, and study the relations which they 

 have to each other, and we would seek to understand their use ; 

 afterwards, we should again put together all these pieces, and by 

 re-establishing their mutual relations restore what we had taken 

 from them ; that is, their movements and their play. 



Now, what the watchmaker does to obtain exact knowledge of 

 a watch, the naturalist does, as far as he is capable, to study an 

 animal or a plant ; by dissection he examines the interior of its 

 body, separates the different organs, determines their relations, 

 and studies their form and nature ; then he observes their play 

 during life, and, by making experiments, becomes acquainted 

 with their uses. Unfortunately the naturalist cannot do all that 

 the watchmaker does; he can destroy, but he cannot re-construct 

 what he has deranged, and restore movement to organs which 

 he has separated to study their structure nevertheless, by anato- 

 mical investigation, by observation of the vital phenomena and by 

 physiological experiments, he ascertains the mechanism of these 



1 4. Whiit is anatomy ? what does it teach ? 



15 Wh it is physiology ? what does it teach ? what is animal physi- 

 ology ? what is vegetable physiology ? 



16. Why is a knowledge of anatomy and physiology necessary to under- 

 stand natural history ? 



