440 



INDEX 



Nephridia, 209, 210. 

 Nerve cell, 189. 

 Nerve fiber, 402. 

 Nerve unit, 403. 

 Nerves, cranial, 405; 



motor, 402, 405; 



sensory, 402, 406; 



vasomotor, 359. 

 Nervous system, central functions of, 

 in frog, 403 ; 



cerebro-spinal in frog, 402 ; 



cerebro-spinal in man, 401; 



divisions of, 400; 



general functions of, 400; 



sympathetic, 406. 

 Neuroptera, 243. 

 Nicotine, a deadly poison, 329. 

 Nictitating membrane, 279. 

 Nitrogen, 18; 



amount of, in air (Exp.), 19; 



needed for plant growth, 94. 

 Nitrogen-fixing bacteria, 94. 

 Nomenclature, botanical, 150. 

 Notebook, use of, 13. 

 Nucleolus, 26. 

 Nucleus, 25; 



in ovule, 33, 34; 



in Spirogyra, 175; 



in yeast, 166. 

 Nut, 54. 

 Nutrients, cost of, 324; 



defined, 20; 



fuel value of, 320; 



uses of, 319. 



Octopus, 268. 



One-celled plants and animals, 183. 



Opossum, Virginia, 311. 



Organ, defined, 24. 



Organic matter, classified, 19; 



relation to inorganic, 28. 

 Organism, defined, 24. 

 Osmometer, potato, 90. 

 Osmosis, defined, 89; 



importance of, 90; 



in root hair, 89. 

 Osmotic pressure, 90. 

 Ostrich, African, 302. 

 Ovary, 31, 33; parts of, 32. 



Ovule, development of, 34; 



fertilization of, 33. 

 Oxidation, defined, 16; 



heat the result of, 17; 



in a match, 16; 



in amoeba, 182; 



in human body, 80; 



slow (Exp.), 17. 

 Oxygen, given off by green leaves, 

 132; 



preparation of, 16; 



properties of, 16. 

 Oyster drill, shell bored by, 266. 

 Oysters, artificial breeding of, 263; 



asymmetry in shell of, 263 ; 



economic importance of, 264; 



typhoid bacillus in raw, 264. 



Palisade layer, 130. 



Palmate venation, 123. 



Pancreas, 330, 339. 



Papilionaceous corolla, 36. 



Pappus, 59. 



Paramcecium, locomotion in, 180; 



reproduction in, 181; 



response to stimuli, 180; 



study of, 179. 

 Parapodia, 211. 



Pasteur's solution, formula for, 167. 

 Pearls and pearl formation, 269. 

 Pectoral girdle, in birds, 295; 



in frogs, 374; 



in man, 374. 

 Pelvic girdle, in birds, 295; 



in frogs, 371, 374; 



in man, 372, 374. 

 Perching, adaptations for, 293. 

 Pericardium, use of, 352. 

 Pericarp, defined, 50. 

 Perithecium, 166. 

 Pepo, 52. 



Peptone, defined, 337. 

 Petiole, 126. 

 Petal, 31, 38. 

 Phanerogams, 151. 

 Phoebe, nest of, 297. 

 Photosynthesis, chemical action in, 

 133; 



compared with milling, 131. 



