Page:Jardine Naturalist's Library Foreign Butterflies.djvu/41

Rh that they ought to have produced important changes.

It will likewise be observed as an important defect in Lamarck's argument, that he can cite no positive fact to exemplify the substitution of some entirely new sense, faculty, or organ, in the room of some other suppressed as useless. "All the instances adduced," says Mr. Lyell, "go only to prove that the dimensions and strength of members, and the perfection of certain attributes may, in a long succession of generations, be lessened and enfeebled by disuse; or, on the contrary, be matured and augmented by active exertion, just as we know that the power of scent is feeble in the greyhound, while its swiftness of pace and its acuteness of sight are remarkable; that the harrier and staghound, on the contrary, are comparatively slow in their movements, but excel in their sense of smelling. We point out to the reader this important chasm in the chain of the evidence, because he might otherwise imagine that we had merely omitted the illustrations for the sake of brevity; but the plain truth is, that there were no examples to be found, and when Lamarck talks of 'the efforts of internal sentiment,' 'the influence of subtile fluids,' and the 'acts of organization,' as causes whereby animals and plants may acquire new organs, he gives us names for things, and with a disregard of the strict rules of induction, resorts to fictions, as ideal as the