The second part of Mr. Youmans’ article regards the theory of evolution. This theory assumes that the immense diversity of living forms now scattered over the earth has arisen from gelatinous matter through a long process of gradual unfolding and derivation within the order of nature (that is, without supernatural interference) and by the operation of natural laws. Mr. Youmans says that this theory “is built upon a series of demonstrated truths.” This assertion would have some weight, if such a building had not been raised in defiance of logic; but we have already shown that Prof. Huxley’s _Three Lectures on Evolution_ teem with fallacies most fatal to the cause he desired to uphold. Hence, while we admit that “demonstrated truth” is a very solid ground to build upon, we maintain that not a single demonstrated truth can be logically alleged in support of the theory of evolution. But let Mr. Youmans speak for himself: “It is a fact accordant with all observation, and to which there never has been known a solitary exception, that the succession of generations of living things upon earth is by reproduction and genetic connection in the regular order of nature. The stream of generations flows on by this process, which is as much a part of the settled, continuous economy of the world as the steady action of gravity or heat. It is demonstrated that living forms are liable to variations which accumulate through inheritance; that the ratio of multiplication in the living world is out of all proportion to the means of subsistence, so that only comparatively few germs mature, while myriads are destroyed; that, in the struggles of life, the fittest to the conditions survive, and those least adapted perish. It is a demonstrated fact that life has existed on the globe during periods of time so vast as to be incalculable; that there has been an order in its succession by which the lowest appeared first, and the highest have come last, while the intermediate forms disclose a rising gradation. It is a demonstrated truth of nature that matter is indestructible, and that, therefore, all the material changes and transformations of the world consist in using over and over the same stock of materials, new forms being perpetually derived from old ones; and it is a fact now also held to be established that force obeys the same laws. All these great truths harmonize with each other; they agree with all we know of the constitution of nature; and they demonstrate evolution as a fact, and go far toward opening to us the secondary question of its method.”