Prejudice, def., 576 



Preservation, of food, 384-385 



Prevention, of disease, 322-334, 338-342, 343-358, 



359-371 

 Primary germ layers, 426 



Primary sex cells. 460-461, 461; dihybrid, 472 

 Prolific, def., 385 

 Protective resemblance, 560-561 

 Proteins, 110, 112; in common foods, 172; in diet, 



174; diffusion of, 124; digestion of, 194; synthesis 



of, 142-143: test for, 116 

 Proterozoic era, 533, 534, 535 

 Prothallus, of fern, 446, 445-446; of flowering plant, 



446 

 Protococcus, 74 

 Protoplasm, 105, 111, 125, 126; composition of, 108- 



109; compounds in, 109-110; contractility of, 269; 



elements in, 108, 109, 108; irritability of, 269; 



structure of, 108; summary of, 111-112 

 Protozoa, 15, 61-64, 62, 64, 66; behavior of, 265- 



266, 266, 269, 269; of malaria, 349-351, 350, 351; 



and symbiosis, 374; tropisms of, 266, 301 

 Pseudopod, 63 

 Psittacosis, 340 

 Psychiatrist, def., 368; 369 

 Psychologist, def., 286; 368 

 Psychozoic era, 533, 534, 539-540 

 Pteridophytes, 72, 79-80, 91 

 Ptyalin, 190, 191 



Public health, 343-371; disposal of sewage, 344-345 

 Pulmonary, artery, 213, 219; circulation, 219, 219- 



220; tuberculosis, 322; vein, 220 

 Pulse, 215 

 Puma, 97 



Pupa, 42; of ant, 47; of mosquito, 352 

 Pupil, of eye, 280 

 Pupillary reflex, exercise, 267 

 Pure, bacterial culture, 314; gamete, 466 

 Pure Food and Drug Act, 385 

 Pus, 210; in skin, 242-243 

 Pustules, of cowpox, 325 



Puzzle box, and cat, 291; and man, 294-295 

 Pyloric sphincter, 195-196 

 Pylorus, 195 



Pyramidal cells, of brain, 276 

 Pyridoxin, 180 

 Pythons, 28, 29 



Quail, 264 



Quarantine, def., 343 



Queen Anne's lace, 88 



Quinine, 89; and malaria, 332-351 



Rabbit, 18; and web of life, 381; reproduction of, 

 432-433 



Rabies, 324-325 



Races, def., 573; blood groups in, 575; classification 

 of, 573-574; of man, 575; misuse of term, 575- 

 576; prejudice, 576-577; table of human, 574 



Radiation, of heat, 241 



Radioactive elements, 250 



Radium, and cancer, 361 



Ragweed, 90, 366; and hay fever, 364-365 



Ratios, Mendelian, 466-467, 467, 469, 471, 508; 

 dihybrid, 472 



Rats, 18; dietary experiments on, 175; extermina- 

 tion of, 347; as germ carriers, 348; and learning, 

 291 



Rattlesnake, 27, 27; head, 27 



Pay flowers, 89-90, 89 



Reasoning, and learning, 294-295; and lower ani- 

 mals, 295-296; tools for, 296 



Pieceiving gamete, 416, 416 



Receptors, 261, 278, 279-282; of ear, 281-282; of 

 eye, 280-281; internal, 280; in reflex arc, 277-278 



Recessive characters, 468, 469, 470, 471, 473; def., 

 268; in man, 509; mutations, 478-480 



Recombination, and variation, 474 



Rectum, 188, 189 



Red corpuscles, 208, 209-210; and malaria, 350-351 



Red Cross, 233 



"Red snow," 74 



Redi, and spontaneous generation. 411 



Reduction, of chromosome. number, 460-461 



Reduction division, def., 460; female primary sex 

 cell, 461; and heredity, 466; and independent 

 assortment, 471-472; male primary sex cell, 461 



Redwoods, giant, 156 



Reed, Walter, and yellow fever, 352 



Reflex arc, 277-279, 278 



Reflexes, 262-263, 287, 288, 298; in frog, 279; and 

 habits, 292-293; in protozoa. 265 



Reforestation, 402; chart, 400 



Regeneration, in starfish, 56; of nerve, 275-276 



"Reindeer moss," 77 



Relationships, of living things (ecology), 373-409 



Rennin, 194 



Repellents, def., 395 



Reproduction, 125, 411-453; ameba, 413, 412-413; 

 of aphids (plant lice), 424; bird, 430-432; fern, 

 445-447; fern versus flowering plant, 446-447; 

 fish, 423-427; frog, 427-429; in land-living ani- 

 mals, 429; and insect life histories, 41-42; malarial 

 protozoan, 350-351; mammal, 432-434; moss, 

 447; organs of, 421; Paramecium, 412, 412; pa- 

 rental care in fish, 427. 430 ; rabbit, 432-433 ; spiro- 

 gyra, 415-416; by spore formation, 414-415; and 

 survival. 434; vegetative, 447-449; yeast, 413- 

 414; 413 



Reproductive organs, 421, 442; bird, 430; flowering 

 plant, 439-442, 439, 440, 441, 442; frog, 422; 

 origin in embryo, 426-427; rabbit, 432-433 



Reptiles. 26-30, 26, 27, 28, 29, 30; Age of, 537-538; 

 brain, 273; embryo, 549; fossil, 537; skeleton, 28, 

 548 



Resemblances, among vertebrates, 547; and classi- 

 fication, 551; chemical, 550, 550; in embryos, 548- 

 550, 549; explanation of embryonic, 550; explana- 

 tion of structural, 548; protective, 560-561, 560, 

 561 ; in skeleton, 547, 548, 549 



Reservoirs, and water supply, 345 



Resin. 82 



Respiration, 119, 125, 226 236; animal compared 

 with plant, 144; and breathing, 231; cellular, 231 ; 

 compared with photosynthesis, 143-145; plant, 

 143-144; summarized, 145 



Response, 260 1508: ameba, 265; conditioned, 288- 

 289; learned, 289-290; Paramecium, 266; plant. 

 301-306; to stimulus. 261; types, 261-262; un- 

 learned, 262-263; vorlicella, 269 



Retina, of eye, 280-281, 280 



Retted, def., 384 



Rh factor, 212 



Rhizopus, 77, 414; reproduction of, 414-415, 414 



Rhodesian man, 568 



Riboflavin, 180, 183; in common foods, 173 



Ribs, 228, 23! 



Rice, 84, 141; and hnilxTi, 177 



Rickets, 180, 181, 181, 183, 311 



Ringer's solution, 135 



Ringworm, 243, 311 



612 



