They are to us, let us say, as they are to Mr. Huxley, identical in power, in form, and in substance; and yet on all these several thousand little bits of apparently indistinguishable matter an element of difference so pervading and so persistent has been impressed, that of them all, not one is interchangeable with another! Each seed feeds its own kind. The protoplasm of the gnat will no more grow into the fly than it will grow into an elephant. Protoplasm is protoplasm; yes, but man's protoplasm is man's protoplasm, and the mushroom's the mushroom's." (Dr. Sterling, _"As Regards Protoplasm."_) Hence we are compelled to acknowledge not an identity of protoplasm in all substances, but an infinite diversity. It follows that the derivation of all plant and animal forms from an original speck or germ of living matter is not only un-proven, but is contradicted by biological science. Darwin himself, like his co-laborer Wallace, was constrained to admit that the origin of life constitutes an unsolved problem. Matter and force do not account for it. Darwin accepted a divine fiat somewhere in the beginning. He says. "There is grandeur in this view of life, with its several powers, having been originally breathed by the Creator into the first forms or into one." In other words, the creation of the first living being was an exceptional kind of power. But if, as Mr. Darwin says, life was breathed by the Creator into the first forms, this constitutes a break in the sufficiency of natural causes alone to produce life. If a special fiat was necessary at this point, why may it not have been at others? If by divine omnipotence, life is believed to have been originated, why shall we not believe that by divine omnipotence the various species of plants and animals were brought forth as related in the first chapter of the Bible? "If the Creator could breathe life into a few forms or into one, as Darwin thinks he did, without violating the law of his own being, and in accordance with the laws which he has established, it seems evident that he might at other times breathe life into other forms in accordance with his laws. I see no necessity for a logic that would compel the Creator to confine the number of his creative fiats to a few, or to one, nor which would limit the fiats to one time." (Fairhurst, _"Organic Evolution Considered."_) Biological Barriers. The atom, the molecule, the life-germ,--these are the barriers which stand against the evolutionistic conception of origins on the physical side. We proceed to investigate the points at which _biology_ touches our problem, and again three barriers call for notice and investigation: The difference between plants and animals; the difference between vertebrates and invertebrates; and the difference between mammals and all other vertebrates.