I will take the present opportunity of insisting upon a suggestion which I made in “Alps and Sanctuaries” (New edition, pp. 152, 153), with which Mr. Tylor was much pleased, and which, at his request, I made the subject of a few words that I ventured to say at the Linnean Society’s rooms after his paper had been read. “Admitting,” I said, “the common protoplasmic origin of animals and plants, and setting aside the notion that plants preceded animals, we are still faced by the problem why protoplasm should have developed into the organic life of the world, along two main lines, and only two—the animal and the vegetable. Why, if there was an early schism—and this there clearly was—should there not have been many subsequent ones of equal importance? We see innumerable sub-divisions of animals and plants, but we see no other such great subdivision of organic life as that whereby it ranges itself, for the most part readily, as either animal or vegetable. Why any subdivision?—but if any, why not more than two great classes?” The two main stems of the tree of life ought, one would think, to have been formed on the same principle as the boughs which represent genera, and the twigs which stand for species and varieties. If specific differences arise mainly from differences of action taken in consequence of differences of opinion, then, so ultimately do generic; so, therefore, again, do differences between families; so therefore, by analogy, should that greatest of differences in virtue of which the world of life is mainly animal, or vegetable. In this last case as much as in that of specific difference, we ought to find divergent form the embodiment and organic expression of divergent opinion. Form is mind made manifest in flesh through action: shades of mental difference being expressed in shades of physical difference, while broad fundamental differences of opinion are expressed in broad fundamental differences of bodily shape. Or to put it thus:— If form and habit be regarded as functionally interdependent, that is to say, if neither form nor habit can vary without corresponding variation in the other, and if habit and opinion concerning advantage are also functionally interdependent, it follows self-evidently that form and opinion concerning advantage (and hence form and cunning) will be functionally interdependent also, and that there can be no great modification of the one without corresponding modification of the other. Let there, then, be a point in respect of which opinion might be early and easily divided—a point in respect of which two courses involving different lines of action presented equally-balanced advantages—and there would be an early subdivision of primordial life, according as the one view or the other was taken.