From all that I have just said it will be understood that the Gospel of Evolution has a wider significance than popular notions imply. The general idea, as to Evolution, that it is synonymous with Darwinism, is not accurate. The Darwinian teaching is only a part, though in one sense it is the most important part, of the Evolution truth. Evolution itself means, as we have seen, the unity of phenomena. All things are, according to this new principle, one huge continuity. Whilst Darwinism shows that man is not distinct from the lower animals, and that all species of animals, and all species of plants are artificial groups gliding one into the other, just as in their gradual development they glided one out of the other, Evolution goes further than this and does not fare worse. For the evolutionist not only believes that which the works of Darwin have made an assured truth, but he believes that plants and animals have had a common parentage, that living matter has originated from the non-living, that there has been no break in the vast series of phenomena at any point. Some of the general grounds for this belief have been given. Let us look rapidly at some of the more special. The principle of the conservation of energy already mentioned indirectly is, in a sense, the starting point of thought on this subject. Grove's essay on the "Correlation of the Physical Forces," published a few years since, was the first clear enunciation of the generalisation towards which so many observations had led. When he reminded men that chemical action, electricity, heat, sound, light, magnetism, and life were all convertible, one into the other, and thus convertible in definite numerical proportions, mathematically calculable, the keynote of the idea of Evolution had been struck.