INDEX 



525 



in lower, 330; kinds of, 477, 480; 

 movements in, 37-38; seed-bearing, 

 478 ; sensitive, 361 ; useful, and in- 

 sects, 417 



Plasma, 182 



Plasmodium of malaria, 404 



Play, 513 



Plumage, color changes in, 286 



Plumbing, regulation of, 395 



Poisons, 118, 131 ff., 194-195, 253 ff., 

 355; fatigue, 208; in soil, 67 



Polar bodies, 459 



Pollarded trees, 271 



Pollen grain, 324, 478 



Pollen tube, 303, 324 



Pollenation, by birds, 306, 307 ; close 

 and cross, 305 ; cross, 442 ; of fig, 

 311; function of, 304; by hand, 

 313; by insects, 309, 311 ; obstacles 

 to close, 305 ; self, 304 ; by water, 

 308 ; by wind, 308 



Pollution, of air, 396; of water, 122, 



39 2 



Polycotyls, 34 



Polymorphic flowers, 305-307 



Population, and climate, 339 ; pres- 

 sure of, 342, 472 



Porifera, 482 



Posture and breathing, 152 



Potato, Burbank, 454 



Practice and learning, 249 



Prairie dogs, 370 



Praying mantis, 372 



Precipitin, 193 



Precipitin test, 197 



Predatory insects, 374 



Predatory relations, 341 



Prepotency, 307 



Preservatives in food, 125, 126 



Pressure, atmospheric, 340 



Primates, 486 ; families of, 487 ; limbs 

 of, 490; and man, 491-492; skele- 

 tons of, 491 ; skulls of, 492 



Primitive man, sec Man 



Production, cost of, 506 ; of necessi- 

 ties, 514 



Prohibition of alcohol, 142 



Propagation, by roots, 48 ; vegetative, 

 269 (see also Regeneration) 



Protection, of birds, 426 ; against in- 

 fection, 388; of young, 371 



Protective activities, 368 



Protective appearances, 351 



Protective armors, 345 



Protective coloration, 352 



Protective invisibility, 352 



Protective mimicry, 357 



Protective movements, 360 



Protective resemblance, 354 



Protein, 51, 52; daily need, 90, 93; 

 danger of excess of, 90, 104, 107 ; 

 digestibility of various kinds, m~ 

 digestion of, 35, 83 ; nutritive ratio, 

 97 ; origin of, 55, 60 ; specific 

 effects of, 107, 108, 109 



Prothallus, 322, 323 



Protoplasm, 21, 24, 80, 131, 132, 181, 

 224, 228, 229, 265, 275, 287, 291, 

 295, 298, 302, 303, 337, 490 ; hered- 

 ity and, 457 ; light destructive to, 

 38,339; movements of, 21 ; needs 

 of, 50 



Protozoa, 295, 341, 404, 482 



Protozoon, 294 



Proventriculus of bird, 87 



Psychology, 498 



Ptarmigan, 286 



Pteridophytes, 481 



Pulmonary artery, 187 



Pulse, 190 



Punnett, Professor R. C., 358 



Pure lines, 442 



Pure races, 447, 455 



Purpose, 222-223, 225, 310, 332, 358, 

 369, 433-434, 49 8 > 59 



Pylorus, 82 



Quarantine, 395 

 Quills, 350 



Rabbits accustomed to poison, 132 



Rabies, 395 



Rats and bubonic plague, 410, 510 



Ray (fish), 373 



Reaction of organism, general, 224 ; 

 and nerves, 217 



Recapitulation in development, 278 



Recessive character, 444 ff., 450 ff. ; 

 in man, 455 



Reclamation, 68 



Recombination of characters, 455 



Rectum, 82 



Red-headed woodpecker, 428 



Reduction division, 459 



Reed, Dr. Walter, 407 



Reflex, 217 ff., 498; as adaptation, 

 244; chains, 244; without conscious- 

 ness, 222 ; nerve connections in, 

 221 ; using an animal's, 217 



Refrigeration, 390 



