428 



INDEX 



Mucus cells, 299. 



Muscles and bones, hygiene, 268. 



Mutations, 253, 406. 



Mutual aid between flowers and 



insects, 41. 

 Mycelium, 133. 

 Myriapoda, .185. 



Natural environment, 25 ; 



selection, 253. 

 Nectar, 35. 

 Need, of food, 272 ; 



of sleep, 356 ; 



of ventilation, 335. 

 Needs of living things, 266. 

 Nerve cells and fatigue, 356 ; 



vasomotor, 325. 

 Nervous control, 181 ; 



of heart, 325 ; 



of respiration, 334 ; 



of sweat glands, 343. 

 Nervous system, 271, 349 ; 



of frog, 352. 

 Neuron, diagram, 351. 

 Newt, 187. 

 Nicotine, 293. 



Nictitating membrane of frog, 242. 

 Nitrates, 80. 

 Nitric acid, 61. 

 Nitrogen, 80 ; 



cycle, 162; 



fixing bacteria, 80, 81, 151 ; 



of air, 20. 

 Nodules, 81. 



Normal heat output, 285. 

 Nose and throat, diseases, 340. 

 Nucleus, 50. 

 Nutrients, 273, 274 ; 



fuel values, 277 ; 



in common foods, 275. 



Object of a field trip, 28. 

 Oils, test for, 61. 

 Operculum, 234. 

 Ophidia, 189. 

 Orbit of eye, 360. 

 Orchard fruits, 124. 

 Organic matter, 64. 

 Organic nutrients, 60. 



Organisms, 47. 

 Organs, 47, 48, 180 ; 



of Corti, 360 ; 



of excretion, 340 ; 



of hearing, 358 ; 



of respiration, 330 ; 



of taste, 358 ; 



of touch, 357. 

 Orthoptera, 30. 

 Osmosis, definition, 75 ; 



experiment, 100 ; 



physiological importance, 77. 

 Ostrich, 191. 



Outline of courses, 407-414. 

 Ovaries of frog, 243. 

 Ovary, 36. 

 Ovules, 54. 

 Oxidation, 64 ; 



in our bodies, 65. 

 Oxygen cycle, 161 ; 



given off by green plants, 95 ; 



of air, 20 ; 



of water, 20. 

 Oyster, 199, 200. 



Packard (zoologist), 33. 

 Palate, hard and soft, 301. 

 Palisade tissue, 86. 

 Pancreas, 305 ; 



of frog, 243 ; 



work of, 305. 

 Papillae, 301. 

 Pappus, 57. 

 Paramoecium, 167, 168, 169; 



needs of, 266 ; 



response to stimuli, 167. 

 Parasites, 131. 



Parasitic animals cause disease, 227. 

 Parasitism, cost and remedy, 263. 

 Parotid, 299. 

 Pasteur, Louis, 401. 

 Pasteurization, 146. 

 Pea pod, 55. 

 Pearls, 206. 

 Pectoral fin, 233. 

 Pelvic fin, 233. 

 Pepsin, 303. 

 Peptic gland, 304. 

 Perfumes, 205. 



