Glossary 



385 



terms, basal in Darwin's famous 

 hypothesis of heredity, mean all- 

 generator and all-generative only 

 in the sense that all parts of the 

 body of the organism give oif 

 gemmules (which see), which 

 assemble in the germ-cells to en- 

 able these to ?*eproduce the or- 

 ganism. Thus the pan, or all- 

 generative power was conceived 

 as having its original "seat" in 

 the organism all-in-all. In other 

 words Darwin's speculation was 

 almost diametrically opposed to 

 the transformation it has under- 

 gone latterly, especially in the 

 prolific mind of Weismann, the 

 germ cells alone, or rather the 

 germ-plasm being the all-genera- 

 tor, according to these specula- 

 tions. 



PARATHYROIDS. Small glands lying 

 near the thyroid but not func- 

 tionally connected with the lat- 

 ter. 



PARTHENOGENESIS. Reproduction 

 .by means of unfertilized eggs. 



PELLICULA. The cuticle or outer- 

 most body membrane in some 

 unicellular and other low organ- 

 isms. 



PHASE. This old and familiar word 

 has taken on new and greater 

 importance, both scientific and 

 philosophic, with the recent ad- 

 vance of knowledge in the region 

 of over-lap between physical and 

 chemical phenomena, this ad- 

 vance making what is generally 

 called physical chemistry. A 

 phase in pure physics, as it may 

 be called, has reference to the 

 position of the particles of a 

 body when the particles are un- 

 dergoing change. For example, 

 corresponding particles in two 

 succeeding waves of water or air 

 are in the same phase. In phys- 

 ical chemistry phase has refer- 

 ence not to position but to state 

 or condition of the constituent 

 particles of a heterogeneous, or 



unlike system. Thus, a combina- 

 tion of liquid water (in common 

 language just water) and solid 

 water, or ice, is a two-phase sys- 

 tem of water. Philosophically 

 viewed, the great significance of 

 phases is that the positions and 

 states of the particles are possible, 

 even conceivable, only in relation 

 to the larger, containing part or 

 whole. Something of the bear- 

 ing of this on the theory of plu- 

 ralism (which see), when this 

 theory is approached from the 

 strictly objective side, will be 

 easily seen. 



PHLOGISTON. An imaginary sub- 

 stance formerly supposed to ex- 

 ist in all combustible bodies, and 

 to be the cause of fire and flame. 

 For nearly a century before the 

 discovery of oxydation as the 

 true cause of fire, by Lavoisier, 

 the phlogistic theory dominated 

 much of chemical science. The 

 chief interest in the theory now 

 is in its relation to the observa- 

 tional and logical processes in- 

 volved in interpreting the gen- 

 erative processes of nature 

 everywhere. The phlogistic the- 

 ory may be taken as a type of 

 elementalistic causal explanation 

 of natural production. 



PHYLOGENIC. Pertaining to phy- 

 logeny, the development of the 

 race; concerning ancestral or- 

 ganisms, real and hypothetical. 



PITUITARY GLAND. A gland of in- 

 ternal secretion, situated at the 

 base of the brain, and connected 

 in the embryo with the roof of 

 the mouth. 



PLURALISM, philosophical (so used 

 in this book). The conception 

 that in its deepest nature the 

 universe is multiform and com- 

 plex; the opposite of Monism, 

 the conception that some single 

 Essence or Substance, more or 

 less known or unknown, is the 

 foundation of all things. 



