Index 
Pangens, 144, 145, 151, 153, 206, 
283. 
Panmixia, 184, 190-192. 
Paramoecium caudatum, 59; re- 
acting to temperature, 363. 
Parasites, 191, 378. 
Particulate inheritance, 144, 150, 
I5I, 153, 154, 156, 302. 
Passion, defined, 393. 
Perigenesis, 259. 
Periodicity of biologic functions, 
350, 351. 
Peripatus, 30. 
Perrier, Edmond; polyzoism, 73. 
Persistence, effect of, 383. 
Pfeffer; formation of cell mem- 
branes, 31. 
Phagocytes, 49. 
Phonograph, 300. 
Physiologic unit; Spencer, 225, 
227, 228; the organism a, 236, 
252. 
Physiological invariability, 361, 
363, 368; a factor in social evo- 
lution, 370 f; tendency to, mne- 
monic, 373. 
Piéron; oysters close when ex- 
posed to air, 364. 
Pigeons, crosses in, 100. 
Pillon; parental love, 382. 
Pineal gland, 11. 
Placenta, 96. 
Planaria maculata, 87, 88, 135. 
Plasticity of the organism, 91, 
94-96, 218. 
Plastids, Ledantec’s, 268 ff. 
Plastidules, Haeckel’s, 259, 316. 
Pleasure and pain, 394. 
Pleuronectids, 217. 
Pluteus, IOT. 
Polymorphism, 311 ff. 
Polyommatus phlaeas, 182, 284. 
409 
Polyzoism, human, 73. 
Post-generation, 21-27, 
81, 96, 134. 
Posthumous action of the nu- 
cleus, 56, 290. 
Fotential elements 
ments). 
Preformation, 6, 106, 119, 120, 
153. 
Preformistic germs, 106-108, 126, 
133, 144, 147-152, 206, 224, 237, 
280, 284, 300. 
Primula acaulis, 152. 
Propitiatory affectivities, 388. 
Protective colors, 182 ff. 
Protective polychromatism, 182. 
Pulst; inheritance of alterations, 
172. 
29, 63, 
(see ele- 
Quinton; tendency to chemical 
invariability, 369. 
Rabe, J.; structure of bone, 126. 
Rana arvalis, Rana _ esculenta, 
Rana fusca, 91, 118. 
Rapidity of division, 75. 
Ray; inheritance of alterations, 
172. 
Recapitulation of phylogeny in 
ontogeny, II, 12, 216, 218, 220, 
228, 243, 250, 260, 263, 268, 273, 
280, 285, 316, 327, 331, 356. 
Reciprocal action of parts of the 
organism, 106. 
Regeneration, 19, 20, 28, 29, 54, 
88, 112, 132, 135, 136, 280, 307; 
cenogenetic, 139-143. 
Rejuvenescence of Infusoria, 353; 
of vital elements, 343. 
Religious sentiment, origin of, 
388. 
Remodeling of tissties, 135. 
