[10] I venture to coin this concise term to signify _the direct inheritance of the effects of use and disuse in kind_. Having a name for a thing is highly convenient; it facilitates clearness and accuracy in reasoning, and in this particular inquiry it may save some confusion of thought from double or incomplete meanings in the shortened phrases which would otherwise have to be employed to indicate this great but nameless factor of evolution. [11] _Origin of Species_, pp. 230-232; Bates's _Naturalist on the Amazons_. Darwin is "surprised that no one has hitherto advanced the demonstrative case of neuter insects, against the well-known doctrine of inherited habit, as advanced by Lamarck." As he justly observes, "it proves that with animals, as with plants, any amount of modification may be effected by the accumulation of numerous, slight, spontaneous variations, which are in any way profitable, without exercise or habit having been brought into play. For peculiar habits confined to the workers or sterile females, however long they might be followed, could not possibly affect the males and fertile females, which alone leave any descendants." Some slight modification of these remarks, however, may possibly be needed to meet the case of "factitious queens," who (probably through eating particles of the royal food) become capable of producing a few male eggs. [12] _Descent of Man_, pp. 573, 572, and footnote. [13] _Contemporary Review_, December, 1875, p. 92. [14] See _Origin of Species_, pp. 5-8. "Changed conditions induce an almost indefinite amount of fluctuating variability, by which the whole organization is rendered in some degree plastic" (_Descent of Man_, p. 30). It also appears that "the nature of the conditions is of subordinate importance in comparison with the nature of the organism in determining each particular form of variation;--perhaps of not more importance than the nature of the spark, by which a mass of combustible matter is ignited, has in determining the nature of the flames" (_Origin of Species_, p. 8). DARWIN'S EXAMPLES.