[28] “Discours sur les révolutions de la surface du globe,” Recherches sur les ossemens fossiles, Ed. iv. t. i. p. 185.
[29] “On the Eclipses of Agathocles, Thales, and Xerxes,” Philosophical Transactions, vol. cxliii.
[30] There is every reason to believe that living plants, like living animals, always respire, and, in respiring, absorb oxygen and give off carbonic acid; but, that in green plants exposed to daylight or to the electric light, the quantity of oxygen evolved in consequence of the decomposition of carbonic acid by a special apparatus which green plants possess exceeds that absorbed in the concurrent respiratory process.
[31] Darwin, “Insectivorous Plants,” p. 289.
[32] I purposely assume that the air with which the bean is supplied in the case stated contains no ammoniacal salts.
[33] The recent researches of Pringsheim have raised a host of questions as to the exact share taken by chlorophyll in the chemical operations which are effected by the green parts of plants. It may be that the chlorophyll is only a constant concomitant of the actual deoxidising apparatus.
[34] “Researches in the Life-history of a Cercomonad: a Lesson in Biogenesis;” and “Further Researches in the Life-history of the Monads.”—“Monthly Microscopical Journal,” 1873.
[35] Excellently described by Stein, almost all of whose statements I have verified.
[36] “Histoire des Sciences Naturelles,” i. p. 152.
[37] The text I have followed is that given by Aubert and Wimmer, “Aristoteles Thierkunde; kritisch berichtigter Text mit deutschen Uebersetzung;” but I have tried here and there to bring the English version rather closer to the original than the German translation, excellent as it is, seems to me to be.