476 



SENESCENCE AND REJUVENESCENCE 



Oogonium, in algae, 316. 



Organism: neo-vitalistic conception of, 9; 

 corpuscular conception of, 11; com- 

 pared with crystal, 16, 199; com- 

 pared with flame, 27; compared with 

 flowing stream, 27, 41, 58, 226; com- 

 pared with machine, 29; Huxley's 

 conception of, 41 ; construction of, by 

 function, 44. See also Individual; 

 Individuation. 



Oxidation: in relation to structure, 28; 

 rate of, in relation to growth, 43; 

 effect of cyanides and narcotics on, 66; 

 decrease in, during narcosis, 68, 71; 

 rate of, in young and old parts of plants, 

 239; rate of, in flower and its parts, 

 349, 374; change in rate of, during 

 development of flower, 375; rate of, 

 after maturation and fertilization in 

 sea-urchin and starfish, 405; increase 

 in rate of, during early embr>-onic 

 development in animals, 412. See 

 also Metabolic rate; Metabolism. 



Oxygen consumption: decrease of, during 

 narcosis, 68; increase of, in stimulated 

 gland cell, 189; after fertilization in 

 sea-urchin and starfish, 405; during 

 early embryonic development, 411. 

 See also Oxidation. 



Paramecium: agamic breeding of, 136; 

 conjugation in, 136; agamic reproduc- 

 tion in, 137; aurelia a,nd caudatum, 138, 

 143; rejuvenescence of, in agamic 

 reproduction, 141; endomixis in, 143; 

 effect of conjugation in, 404. 



Parthenogenesis: in plants, 322 footnote 2, 

 408; in bee, 345, 395; in relation to 

 zygogenesis in invertebrates, 389, 410; 

 in relation to physiological age, 393, 

 406; in relation to rate of egg produc- 

 tion, 394, 395, 408; in trematode 

 larvae, 395; artificial, 405; resem- 

 blance of, to agamic and experimental 

 reproduction, 407; conditions deter- 

 mining, 407; "artificial," 408; grada- 

 tions between, and zygogenesis, 410. 

 See also Fertilization; Gametes. 



Parthenogenic egg: oogenesis of, com- 

 pared with that of zygogenic egg, 343: 

 female-producing and male-producing, 

 390; younger than zygogenic egg, 393, 

 407, 410; germ cell of trematode larva 

 S'S, 39S; general characteristics of, 408. 



Parthenogenic female, in Crustacea, 390. 



Penicillium, spore formation in, 248. 



Pennarla tiarella: susceptibility of, in 

 relation to age, loi; agamic reproduc- 

 tion in, 148, 150; rejuvenescence of, 

 in agamic reproduction, 149, 151. 



Periodicity: in organisms in general, 187, 

 296, 297; in accumulation of carbon 

 dioxide, 188; in fatigue and recovery, 

 188,297; in pancreas cell, 189, 296; in 

 plants, 191; in gametic reproduction, 

 192, 388; in growth, 276, 388; in 

 flowering, 375. See also Age cycle; 

 Life cycle. 



Permeability: role of, in organisms, 24; 

 theories of, 25; in relation to narcotic 

 action, 69. 



Phagocata gracilis, susceptibility of, in 

 relation to age, loi. 



Phytoid, 237, 239. 



Plagiostomum girardi, axial develop- 

 mental gradients in, 205. 



Planaria dorotocephala: reduction of, 

 during starvation, 35, 157; structure 

 of, 92; susceptibility of, in relation to 

 age, 99; reconstitution of, 103; change 

 in susceptibility of pieces of, after sec- 

 tion, 105; reconstitution of, in relation 

 to internal and external factors, in; 

 degrees of reconstitution of, in; 

 rejuvenescence of, in experimental 

 reproduction, 116; rejuvenescence of, 

 in repeated reconstitution, 118; agamic 

 reproduction of, 122; act of fission in, 

 124; prevention of fission in, 125; 

 rejuvenescence of, in agamic repro- 

 duction, 126; rejuvenescence of , during 

 starvation, 157; rate of reduction of, 

 in starvation, 162; acclimation of, 

 during starvation, 165; axial gradients 

 in, 202; dominance and subordination 

 during reconstitution of, 213; limit 

 of dominance in agamic reproduction 

 of, 221; reconstitution of, in narcotics, 

 222; spatial factors of dominance in, 

 222; conditions of gamete formation 

 in, 384. 



Planaria maculata: susceptibility of, in 

 relation to age, 93; time not a measure 

 of age in, 97; agamic reproduction in, 

 124; rejuvenescence of, in agamic 

 reproduction, 126. 



Planaria simplicissima, biaxial posterior 

 ends in, 215. 



Planaria velata: susceptibility of, in 

 relation to age, loi; agamic reproduc- 

 tion of, 130, 169; rejuvenescence of, 

 in agamic reproduction, 132; inhibi- 

 tion of senescence in, 165; senescence 

 of, in relation to character of nutrition, 

 169; involution in, 171. 



Plumaklla fungosa, oogenesis of, 340. 



Polarity, physiological, occurrence of, 

 200. See also Axes: Dominance; 

 Individual; Individuation. 



