Palm stems, 157 



Panama Canal, and mosquito extermination, 353 



Pancreas, 192: and diabetes, 251-252; stimulation 



of, 199-200 

 Pancreatic, 196; activation of juice, 197; ducts, 195; 



juice, 192, 195, 196 

 Pantothenic acid, 180 



Paramecium, 62, 63, 118; behavior of, 266, 266; con- 

 jugation of, 417; reproduction of, 412, 412 

 Parasites, 311; causing disease, 311—358; large, 354- 



355: of plants, 386-387 

 Parasitism, 311, 373, 374 

 Parathyroid, 254-255 

 Paratyphoid, statistics, 326 

 Parenchyma, 133 



Parental care, 430; in birds, 431-432, 431; in cray- 

 fish, 430; in fish, 427. 427; in frogs, 430; in insects, 



430, 430; \n mammals, 433-434 

 Paris green, and insects, 393 

 Parrot fever, 340 

 Parsley family, 87-88, 88 

 Parthenogenesis, def., 424; artificial, 424; in plants, 



449 

 Passenger pigeons, extinction of, 405 

 Passive immunity, 328-329: for tetanus, 331 

 Pasteur, Louis, 332; compared with Jenner, 326; 



and disease, 322-325; and immunity, 323-325; 



and pasteurization, 345; and rabies, 324-325; and 



spontaneous generation, 411-412; and viruses, 



340; and wine, 322-323 

 Pasteur Institute, and bacteriophage, 340-341 

 Pasteurization, of milk, 345-346; test of, 346 

 Pathogenic, def., 311 

 Pathogenic bacteria, 311, 313, 315, 316; and body's 



defenses, 315-316; and spores, 314; strains of. 338 

 Pavlov, Ivan, 9-10; and conditioned response. 288 

 Pea, characters studied, 468; chromosome number 



of, 459; heredity in, 467-472; pod, 444; tall 



X short cross, 469 

 Pearl, Raymond, and tobacco, 365-366 

 Peat, 78 



Pecan tree, grafting, 503 

 Pedigree, def., 497, 508; of famous family, 512; of 



man, 511-512; and shortsightedness in man, 509; 



and skin condition in man. 509 

 Peking man, 566; excavating for, 567 

 Pellagra, 179, 183 

 Penicillin, 12, 13, 77, 334; and mold, 333; and 



syphilis, 332 

 Pepsin, 194 

 Peptone, 194 

 Perching birds. 22 

 Perennials, def., 80 

 Peristalsis, 193, 196, 198 

 Peritonitis, 362 

 Permeable, def., 124 

 Petals, 439; of lily, 439 

 Petiole, 137 



Petri dish, for studying bacteria, 313; 323 

 Petrifaction, def., 526 

 Petrified, egg, 526; tree, 526 

 Phagocytes, 210, 210; and bacteria, 315 

 Pharynx, of earthworm, 57 



Phloem, 153, 156, 157; of root, 152; of stem, 154 

 Phosphatase, in milk. 346 



Phosphorus (P). 109, 111; in common foods, 173 

 Photosynthesis, 140-142; summarized, 145 

 Phototropism, 301; negative, 301; of nasturtium, 



301; positive, 301 

 Phylum, annelids, 57; arthropods, 41-53; bryo- 



phytes, 78; coelenterates, 58-60; def., 15; echino- 



derms, 5.5-56; fiatworms, 58; invertel, rales, 39- 



71, 40; mollusks, 53-55; porifera (sponges). 61; 



pteridophylos. 79-80: roundworms, 57; spermato- 



phyles, 80-90; thallophytes, 73-78; vertebrates, 



16-39, 16 

 Pig, effect of environment on. 486; and tapeworm, 



355; and trichinosis, 354-355 

 Pigeons, ex{)eriments on brain, 272-273 

 Pigeon-wheat, a moss, 73; 447 

 Pigment of skin, protection against ultraviolet 



rays, 242 

 Pimples, 242-243 

 Pine, 72, 81-82: beetle. 390; and environment, 488; 



needles. 82, 137; and rust, 386 

 Pineal gland, human, 271 

 Pisces, 65 (see Fish) 

 Pistil, 439, 439; after fertilization, 443; of flower, 



440-441 

 Pistillate, def., 440 

 Pitcher plant, 305 

 Pith, 154; in monocots, 157 

 Pithecanthropus erectus, 566, 567 

 Pituitary gland, 253-254, 271; over-secretion, 247; 



under-secretion. 253 

 Placenta, def., 433; 432; of pea plant, 452 

 Plague, bubonic, 328, 343, 348; and quarantine, 343 

 Planaria, 40, 58, 58 



Plant lice. 46; control of, 394; reproduction of, 424 

 Plants, 7 94: behavior of, 301-306; breeding, 493- 



507; classification of, 90-91; competition among, 



385; families, 72-94; food-making, 137-165, 142; 



and growth hormones, 303-304; importance of 



green, 144-145; insect-eating, 304-305. 306; 



movement of water in, 158-159; organs, 131, 133; 



phyla, 72; reproduction of, 438-453; structure of, 



137-165: tissues, 133; unusual behavior of, 304- 



305; useful, 88; uses of, 382-383 

 Plasma, 211, 220, 221; membrane, 106; of blood, 



208-209 

 Platelets. 208, 209; and clotting, 210-211 

 Pleura, 227, 230 



Plexus, of autonomic system, 279, 279 

 Plumule, 451 

 Pneumococcus, 338 



Pneumonia, 338; and sulfa drugs, 334; vaccine, 339 

 Poison hemlock, 88 



Poisons, contact, 394-395; stomach, 393-394 

 Polar bear, 99 

 Poliomyelitis, 230, 340 

 Polled (cattle), def., 497 

 Pollen, and allergy, 365; def., 441; development of 



grain, 442, 442; grain, 442, 442; tube, 442, 443 

 Pollination, 441 



Pollution, of water supply, 344—345 

 Pollywog, 428 

 Polydactyly, def., 509 

 Polynesian, 575 

 Polyneuritis, 177 

 Poplar leaf. 85 

 Pores, of skin, 239 

 Pork, and parasites, 354—355 



Positive tropism, 266, 301. 301, 302. 302, 303-304 

 Postulates, of Koch, 322 



Potassium, 109, 111; chlorate, 127; o.xalate, 224 

 Potato. 87, 141; beetle, 390-391, 391, 397; cells, 



143 ; economics of, 390-391 ; vegetative reproduc- 

 tion of, 448 

 Poverty, and health, 370 

 Pouched mammals, 18-20, 19, 433, 433 

 Praying mantis, 45, 45 

 Prehistoric, ages, 564-573, 577; men, 564-573, 577 



611 



