The statement in this passage that "Darwin was well aware that ordinary variability has nothing to do with evolution, but that other kinds of variation were necessary" is contradicted by many passages in the "Origin". A.C.S.)) The latter afford the material for natural selection to act upon on the broad lines of organic development, but the first do not. Fortuitous variations are the species-producing kind, which the theory requires; continuous fluctuations constitute, in this respect, a useless type.英文原著 · 《Darwin and Modern Science》
If, then, progress was to be made in Genetics, work of a different kind was required. To learn the laws of Heredity and Variation there is no other way than that which Darwin himself followed, the direct examination of the phenomena. A beginning could be made by collecting fortuitous observations of this class, which have often thrown a suggestive light, but such evidence can be at best but superficial and some more penetrating instrument of research is required. This can only be provided by actual experiments in breeding.英文原著 · 《Darwin and Modern Science》
Bentham has stated this in a striking way: "Fixed and immovable as is the individual plant, there is no class in which the race is endowed with greater facilities for the widest dispersion...Plants cast away their offspring in a dormant state, ready to be carried to any distance by those external agencies which we may deem fortuitous, but without which many a race might perish from the exhaustion of the limited spot of soil in which it is rooted." (Pres. Addr.(1869), "Proc. Soc." 1868-69, pages lxvi, lxvii.)英文原著 · 《Darwin and Modern Science》
There is certainly this much resemblance that a number of quite different sub-injurious agencies produce in the lower organisms a form of reaction by the help of which they, in a partly fortuitous way, escape from the threatening element in their environment. The higher animals are stimulated in a parallel manner to vague and originally purposeless movements, one of which removes the discomfort under which they suffer, and the organism finally learns to perform the appropriate movement without going through the tentative series of actions.英文原著 · 《Darwin and Modern Science》
THE very name of Arthur Wardlaw startled Helen, and made her realize how completely her thoughts had been occupied with another. But add to that the strange and bitter epigram! Or was it a mere fortuitous concourse of words? She was startled, amazed, confounded, puzzled. And, ere she could recover her composure, Hazel was back to his problem again; but no longer with the same energy. He said in a faint and sleepy voice: "'He maketh the winds His messengers, and flames of fire His ministers.' Ah! if I could do that! Well, why not?英文原著 · 《Foul Play》
Maignan saluted obsequiously, and in a moment hurried young Perrot from the room; leaving me to congratulate myself on the strange and fortuitous circumstance that had thrown him in my way, and enabled me to guard against a RENCONTRE that might have had the most embarassing consequences.英文原著 · 《From the Memoirs of a Minister of France》