The first of these gaps which we notice is that between dead and living matter. It is easy to fill this with such a term as protoplasm, which includes matter both dead and living, and so to ignore this distinction; but practically we do not yet know as a possible thing the elevation of matter, without the agency of a previous living organism, from that plane in which it is subject merely to physical force, and is unorganised, to that where it becomes organised, and lives. Under that strange hypothesis of the origin of life from meteors, with which Sir William Thomson closed his address at a late meeting of the British Association, there was concealed a cutting sarcasm which the evolutionists felt. It reminded them that the men who evolve all things from physical forces do not yet know how these forces can produce the phenomena of life even in its humblest forms. It is true that the scientific world has been again and again startled by the announcement of the production of some of the lowest forms of life, either from dead organic matter, or from merely mineral substances; but in every case heretofore the effort has proved as vain as the analogies attempted to be set up between the formation of crystals and that of organized tissues are fallacious. A second gap is that which separates vegetable and animal life. These are necessarily the converse of each other, the one deoxidizes and accumulates, the other oxidizes and expends. Only in reproduction or decay does the plant simulate the action of the animal, and the animal never in its simplest forms assumes the functions of the plant. Those obscure cases in the humbler spheres of animal and vegetable life which have been supposed to show a union of the two kingdoms, disappear on investigation. This gap can, I believe, be filled up only by an appeal to our ignorance. There may be, or may have been, some simple creature unknown to us, on the extreme verge of the plant kingdom, that was capable of passing the limit and becoming an animal. But no proof of this exists. It is true that the primitive germs of many kinds of humble plants and animals are so much alike, that much confusion has arisen in tracing their development. It is also true that some of these creatures can subsist under very dissimilar conditions, and in very diverse states, and that under the specious name of Biology,[BA] we sometimes find a mass of these confusions, inaccurate observations and varietal differences made to do duty for scientific facts. But all this does not invalidate the grand primary distinction between the animal and the plant, which should be thoroughly taught and illustrated to all young naturalists, as one of the best antidotes to the fallacies of the evolutionist school.