444 



INDEX 



Mosses, 152. 



Mucus, 353. 



Muscle tissue, use of, 323. 



Muscles, and skeleton, 324 ; 



arrangement of voluntary, 322 ; 



extensor, 322 ; 



flexor, 322 ; 



nerve endings in, 323 ; 



structure of voluntary, 323. 

 Mushrooms, 151. 

 Mycelium, 149, 151. 

 Myriapods, 246, 247. 



Nails, development of, 321. 

 Narcotics, in common use, 417. 

 Natural resources, conservation of, 



15. 

 Nectar glands, 38, 42. 

 Nectar guides, 42. 

 Nerve, optic, 409 ; 



parts of, 401. 

 Nerve fibers, 399. 

 Nerves, motor, 401 , 402 ; 

 sensory, 401, 402 ; 

 vasomotor, 377. 

 Nervous control, of blood vessels, 

 377; 

 of heart, 377 ; 

 of respiration, 384 ; 

 of stomach, 358 ; 

 of sweat glands, 392 ; 

 organs of, 206. 

 Nervous system, and sense organs, 

 399; 

 cerebro-spinal, 400 ; 

 divisions of, 399 ; 

 function of, 328 ; 

 governing stomach, 358 ; 

 in birds, 302 ; 

 in fishes, 279 ; 

 in man, 328 ; 

 of crayfish, 225 ; 

 of frog, 402 ; 

 of insects, 236 ; 

 sympathetic, 402, 403. 

 Neuroptera, 244, 247. 

 Newt, 292. 

 Nicotine, 349, 417. 

 Nictitating membrane, 286. 

 Nitrogen, in air, 17 ; 



Nitrogen, in plant growth, 94 ; 



properties of, IS. 

 Nitrogen cycle, 186. 

 Nitrogen-fixing bacteria, 94. 

 Nucleolus, 29. 

 Nucleus, 29 ; 



in amoeba, 193 ; 



in paramoecium, 191. 

 Nutrients, 24, 330 ; 



fuel values of, 333 ; 



in beans, 67 ; 



uses of, 332. 

 Nymph, 244. 



Oils, 24, 331. 



Ommatidia, 223. 



One-celled animals, 195. 



Operculum in fishes, 277. 



Opium, 417. 



Orchid, wild, 38. 



Order, defined, 157. 



Organ, defined, 26, 204. 



Organic and inorganic matter, 31. 



Organism, defined, 26. 



Organs of a plant, 27. 



Orthoptera, 247. 



Osculum, 201. 



Osmometer, potato, 90. 



Osmosis, 90 ; 



importance of, 91 ; 



of sugar, 106. 

 Ostrich, African, 308. 

 Ovipositor, 234. 

 Ovule, development of, into seed, 37 ; 



fertihzation of, 37. 

 Oxidation, 19 ; 



heat the result of, 20 ; 



in germination, 77 ; 



in human body, 22 ; 



of carbon, 21 ; 



rapid, 22 ; 



slow, 20. 

 Oxygen, evolved in starch making, 

 125, 147; 



preparation of, 18, 19 ; 



properties of, 19. 

 Oyster, shell of, 268 ; 



and typhoid, 269. 



Palate, hard, 354. 



