ORGAN'S OF DIGESTION. 303 



CHAPTER FIRST. 



ORGANS OF DIGESTION. 



FIRST SECTION. 



General Observations on the Organs of Digestion. 



As an animal is but a moving sac, organized to convert 

 foreign matter into its own likeness, all the complex organs 

 of relation or of animal life serve but to administer to this 

 digestive bag. The bones, connected together by their 

 ligaments, are but the solid levers which enable the muscles 

 to move it to and fro, and the nervous system, with its 

 various organs of sense, serve but to direct its movements 

 in quest of food. The unorganized food of plants is placed 

 by nature in contact with the exterior surface of their body, 

 and their vessels are directed thither to select and absorb it, 

 which roots them through life to the soil where they grow ; 

 but as animals place their food within their stomach and 

 have their roots directed inwards to that central reservoir, 

 they can change their place and move about in quest of 

 what is most congenial to their nature. The organs of 

 animal life relate to this difference between the two organic 

 kingdoms, to the locomotive powers of animals for the 

 selection of their food; but the organs of vegetative life 

 relate merely to the assimilation of food when already within 

 the body, and are, therefore, common to animals with 



