In such a way the reparation of local injuries might be symbolized as a filling up and completion of an interrupted rhythm.

Thus also monstrous aberrations from typical structure might correspond to a discord, and sterility from crossing be compared with the darkness resulting from the interference of waves of light.
Such symbolism will harmonize with the peculiar reproduction, before mentioned, of heads in the body of certain annelids, with the facts of serial homology, as well as those of bilateral and vertical symmetry.

{230} Also, as the atoms of a resonant body may be made to give out sound by the juxtaposition of a vibrating tuning-fork, so it is conceivable that the physiological units of a living organism may be so influenced by surrounding conditions (organic and other) that the accumulation of these conditions may upset the previous rhythm of such units, producing modifications in them--a fresh chord in the harmony of nature--a new species! But it may be again objected that to say that species arise by the help of an innate power possessed by organisms is no explanation, but is a reproduction of the absurdity, _l'opium endormit parcequ'il a une vertu soporifique_.

It is contended, however, that this objection does not apply, even if it be conceded that there is that force in Moliere's ridicule which is generally attributed to it.[231] Much, however, might be said in opposition to more than one of that brilliant dramatist's smart philosophical epigrams, just as to the theological ones of Voltaire, or to the biological one of that other Frenchman who for a time discredited a cranial skeletal theory by the phrase "Vertebre pensante."[232] In fact, however, it is a real explanation of how a man lives to say that he lives independently, on his own income, instead of being supported by his relatives and friends.

In the same way, there is fully as real a distinction between the production of new specific manifestations entirely _ab externo_, and by the production of the same through an innate force and tendency, the determination of which into action is occasioned by {231} external circumstances.
To say that organisms possess this innate power, and that by it new species are from time to time produced, is by no means a mere assertion that they _are_ produced, and in an unknown mode.