come or not, as we remember or forget that our Science is to be based entirely upon experiment, or mathematical deduction from experiment. Men of science [says Tyndall] prolong the method of nature from the present into the past. The observed uniformity of nature is their only guide.[70] The man of science [says Huxley] has learned to believe in justification, not by faith, but by verification.[71] In this manner must we test the Evolution theory, and spontaneous generation as an essential element thereof. We will begin with Professor Huxley's statement of what he styles "the fundamental proposition of Evolution."[72] That proposition is [he writes] that the whole world, living and not-living, is the result of the mutual interaction, according to definite laws, of the forces possessed by the molecules of which the primitive nebulosity of the universe was composed. If this be true, it is no less certain that the existing world lay, potentially, in the cosmic vapour; and that a sufficient intelligence could, from a knowledge of that vapour, have predicted, say the state of the Fauna of Britain in 1869[73] with as much certainty as one can say what will happen to the breath in a cold winter's day. That is to say, the supposed nebula was a vast piece of mechanism, of unimaginable complexity, the component parts of which under the influence of such forces as gravitation, heat, chemical affinity, electricity and magnetism, have produced everything that has since appeared on earth, vegetable and animal life amongst the rest. How are we to assure ourselves that such was really the case? Professor Tyndall has told us that the only scientific method is to prolong the method of nature from the present into the past, taking her observed uniformity for our only guide, and in like manner we have heard it laid down by Professor Romanes, that we must assume as a first principle that the laws of nature are always and everywhere the same, and that by their uniform operation everything is done. It is therefore quite clear that as no man was present when life first made its appearance, to observe and record whence it came, the only way in which we can possibly proceed, without violating every scientific canon, is to argue from what happens now, to what must have happened then,--to show that inorganic matter can in fact generate organic life, and to conclude that the same laws must have worked the same results in the past as they do in the present.