Lamarck’s theories fell into disrepute, partly because they were too startling to be capable of ready fusion with existing ideas; they were, in fact, too wide a cross for fertility; partly because they fell upon evil times, during the reaction that followed the French Revolution; partly because, unless I am mistaken, he did not sufficiently link on the experience of the race to that of the individual, nor perceive the importance of the principle that consciousness, memory, volition, intelligence, &c., vanish, or become latent, on becoming intense. He also appears to have mixed up matter with his system, which was either plainly wrong, or so incapable of proof as to enable people to laugh at him, and pooh-pooh him; but I believe it will come to be perceived, that he has received somewhat scant justice at the hands of his successors, and that his “crude theories,” as they have been somewhat cheaply called, are far from having had their last say. Returning to Mr. Darwin, we find, as we have already seen, that it is hard to say exactly how much Mr. Darwin differs from Lamarck, and how much he agrees with him. Mr. Darwin has always maintained that use and disuse are highly important, and this implies that the effect produced on the parent should be remembered by the offspring, in the same way as the memory of a wound is transmitted by one set of cells to succeeding ones, who long repeat the scar, though it may fade finally away. Also, after dealing with the manner in which one eye of a young flat-fish travels round the head till both eyes are on the same side of the fish, he gives (“Natural Selection,” p. 188, ed. 1875) an instance of a structure “which apparently owes its origin exclusively to use or habit.” He refers to the tail of some American monkeys “which has been converted into a wonderfully perfect prehensile organ, and serves as a fifth hand. A reviewer,” he continues, . . . “remarks on this structure—‘It is impossible to believe that in any number of ages the first slight incipient tendency to grasp, could preserve the lives of the individuals possessing it, or favour their chance of having and of rearing offspring.’ But there is no necessity for any such belief. Habit, and this almost implies that some benefit, great or small, is thus derived, would in all probability suffice for the work.” If, then, habit can do this—and it is no small thing to develop a wonderfully perfect prehensile organ which can serve as a fifth hand—how much more may not habit do, even though unaided, as Mr. Darwin supposes to have been the case in this instance, by “natural selection”? After attributing many of the structural and instinctive differences of plants and animals to the effects of use—as we may plainly do with Mr. Darwin’s own consent—after attributing a good deal more to unknown causes, and a good deal to changed conditions, which are bound, if at all important, to result