"All botanists know that the plants which they transplant from their natal spot into gardens for cultivation there gradually undergo changes which in the end render them unrecognizable. Many plants naturally very hairy, there become glabrous or nearly so; a quantity of those which were procumbent or trailing there have erect stems; others lose their spines or their thorns; finally, the dimensions of parts undergo changes which the circumstances of their new situation infallibly produce. This is so well known that botanists prefer not to describe them, at least unless they are newly cultivated. Is not wheat (_Triticum sativum_) a plant brought by man to the state wherein we actually see it, which otherwise I could not believe? Who can now say in what place its like lives in nature? "To these known facts I will add others still more remarkable, and which confirm the view that change of circumstances operates to change the parts of living organisms. "When _Ranunculus aquatilis_ lives in deep water, all it can do while growing is to make the end of its stalks reach the surface of the water where they flourish. Then all the leaves of the plant are finely cut or pinked.[168] If the same plant grows in shallower water the growth of its stalks may give them sufficient extent for the upper leaves to develop out of the water; then its lower leaves only will be divided into hair-like joints, while the upper ones will be simple, rounded, and a little lobed.[169] This is not all: when the seeds of the same plant fall into some ditch where there is only water or moisture sufficient to make them germinate, the plant develops all its leaves in the air, and then none of them is divided into capillary points, which gives rise to _Ranunculus hederaceus_, which botanists regard as a species. "Another very striking proof of the effect of a change of circumstances on a plant submitted to it is the following: "It is observed that when a tuft of _Juncus bufonius_ grows very near the edge of the water in a ditch or marsh this rush then pushes out filiform stems which lie in the water, are there deformed, becoming disturbed (_traçantes_), proliferous, and very different from that of _Juncus bufonius_ which grows out of water. This plant, modified by the circumstances I have just indicated, has been regarded as a distinct species; it is the _Juncus supinus_ of Rotte.[170] "I could also give citations to prove that the changes of circumstances relative to organisms necessarily change the influences which they undergo on the part of all that which environs them or which acts on them, and so necessarily bring about changes in their size, their shape, their different organs. "Then among living beings nature seems to me to offer in an absolute manner only individuals which succeed one another by generation.