FOOTNOTES:
[41] It is probable that this shortening has resulted not directly but indirectly, from the selection of individuals which were noted for tenacity of hold; for the bull-dog's peculiarity in this respect seems due to relative shortness of the upper jaw, giving the underhung structure which, involving retreat of the nostrils, enables the dog to continue breathing while holding.
[42] Though Mr. Darwin approved of this expression and occasionally employed it, he did not adopt it for general use; contending, very truly, that the expression Natural Selection is in some cases more convenient. See Animals and Plants under Domestication (first edition) Vol. i, p. 6; and Origin of Species (sixth edition) p. 49.
[43] It is true that while not deliberately admitted by Mr. Darwin, these effects are not denied by him. In his Animals and Plants under Domestication (vol. ii, 281), he refers to certain chapters in the Principles of Biology, in which I have discussed this general inter-action of the medium and the organism, and ascribed certain most general traits to it. But though, by his expressions, he implies a sympathetic attention to the argument, he does not in such way adopt the conclusion as to assign to this factor any share in the genesis of organic structures—much less that large share which I believe it has had. I did not myself at that time, nor indeed until quite recently, see how extensive and profound have been the influences on organization which, as we shall presently see, are traceable to the early results of this fundamental relation between organism and medium. I may add that it is in an essay on "Transcendental Physiology," first published in 1857, that the line of thought here followed out in its wider bearings, was first entered upon.
[44] Text-Book of Botany, &c. by Julius Sachs. Translated by A. W. Bennett and W. T. T. Dyer.
[45] A Manual of the Infusoria, by W. Saville Kent. Vol. i, p. 232.
[46] Ib. Vol. i, p. 241.
[47] Kent, Vol. i, p. 56.
[48] Ib. Vol. i, p. 57.
[49] The Elements of Comparative Anatomy, by T. H. Huxley, pp. 7-9.