It should not pass unnoticed in this connection that the stems and the trunks of shrubs and of trees and also many kinds of fruits and nuts are sometimes highly colored. It is true that some of the latter have been supposed to owe their color to its usefulness in attracting birds and other animals which, feeding on the fruit, swallow the seeds, and these, passing through the digestive tract and falling to the ground, may germinate. The dissemination of the seeds of such plants is supposed to be brought about in this way; and since they may be widely disseminated it may be supposed that it is an advantage to the plant to have attracted the attention of the fruit-eating birds. On the other hand one of the most brilliantly colored seeds, the acorn, is too large to pass through the digestive tracts of birds, and is, in fact, ground to pieces in the gizzard, and in the case of several mammals that feed on the acorns, the acorn is crushed by the teeth. It would seem, therefore, that its coloration is injurious to it rather than the reverse, as it leads to its destruction. It has been suggested by Darwin that since the acorns are for a time stored up in the crop of the bird, the passenger pigeon for example, and since the birds may be caught by hawks and killed, the seeds in the crop thus become scattered. Consequently it may be, after all, of use to the oak to produce colored acorns that attract the attention of these pigeons. This suggestion seems too far-fetched to consider seriously. In the case of the horse-chestnut the rich brown color is equally conspicuous, but the nut is too large to be swallowed by any of the ordinary seed-feeding birds or mammals. Shall we try to account for its color on the grounds of the poisonous character of the seed? Has it been acquired as a warning to those animals that have eaten it once, and been made sick or have died in consequence? I confess to a personal repugnance to imaginative explanations of this sort, that have no facts of experience to support them. Changes in the Organism that are of No Use to the Individual or to the Race