XIV PHYSIOLOGY AND MORPHOLOGY OF ANIMALS. 



CHAPTER II. 



NUTRITION PROPER — ANABOLISM — FOOD PREPARATION — DIGESTIVE 

 SYSTEM. 



SECTION I. 



Food and its Uses. 



Definition of food, kinds, 288. Uses, 289. Distinctive uses of 

 kinds, waste tissue used, 290. 



Food Preparation. — The different steps of preparation, 291. 



SECTION II. 

 Mouth Digestion in Vertebrates. 



Salivary glands, 292 ; structure of, 293. Composition and use of 

 saliva, 294. Ferments denned, 295. 



Comparative Physiology of Mouth Digestion in Vertebrates. — Teeth 

 in vertebrates, 295. Mammalian teeth, origin and development of, 

 296. Composition of teeth, kinds of teeth, 297. Variation in teeth: 

 in size, in relative number of the kinds, 298. Dental formula, 299. 

 Structure of molars, 300. Of herbivorous molars, origin of this struc- 

 ture, 302. Mouth armature of whales, 304. Homology of baleen 

 plates, birds, 305. Teeth of extinct birds, reptiles, fangs of serpents, 

 structure of, 306. Origin of mammalian teeth, fishes, kinds of teeth, 

 308. 



SECTION III. 



Stomach digestion — Chymification — Peptonization. 



Saccharization of food, 310. Stomach described, 311. Coats, me- 

 chanical work or chymification, 312. Chemical work or peptonization, 

 313. Composition and uses of gastric juice, effect of, on milk, ab- 

 sorption from stomach, 314. 



Comparative Physiology of Stomach. 



Ruminants, 315. Evolution of ruminant stomach, granivorous 

 birds, digestive apparatus of, 317. Evolution of this apparatus, 318. 



SECTION IV. 

 Intestinal Digestion — Chylification —Em ulsification . 



Form and structure of intestines, 319. Relation to abdominal walls, 

 320. Mesentery, peritoneum, 321. Coats of the intestines, mechan- 

 ical work, 322. Chemical work, action of bile, 323. Of pancreatic 

 juice, emulsion defined, 324. Absorption, 325. Two modes of, gen- 

 eral course of each to the circulation, 326. Sanguification, 327. Effect 

 of the liver and of the mesenteric glands, portal vein described, 328. 



Modification of process of intestinal digestion in vertebrates, 329. 

 Cecum in a rat, 330. 



