In his third lecture he brings forward what he regards as a demonstration. In the case of Equus, embracing our horse, ass, and zebra he is able, by means of the specimens gathered in the West by Prof. Marsh, to discover the succession of horse-like forms which the hypothesis of evolution supplies. He goes back from the living horse through the like animals of the post-Tertiary in the Pliocene, middle and earlier on to the older Eocene formation, where he finds the orohippus. "There you have four toes on the front-limb complete, three toes on the hind-limb, a complete and well-developed ulna getting forward an equality of size with the radius, a complete and well-developed fibula apparently, though it is not quite certain, and then teeth with their simple fangs. So that you are now able, thanks to these researches, to show that, so far as our present knowledge extends, the history of the horse-type is exactly and precisely that which could have been predicted from a knowledge of the principles of evolution, and the knowledge we now possess justifies us completely in the anticipation that, when the still older Eocene deposits and those which belong to the Cretaceous epoch have yielded up their remains of equine animals, we shall find first an equine creature with four toes in front and a rudiment of the thumb, then probably a rudiment of the fifth behind, and so, by gradual steps, until we come to that five-toed animal in which most assuredly the whole series took its origin. That is what I mean, ladies and gentlemen, by demonstrative evidence of evolution."
Suppose that we admit all that the lecturer claims on this subject: what then? Have we thereby set aside any doctrine of philosophy or religion? The Christian, even the Christian theologian, may say wisely: "Let naturalists dispute as they may about the derivation of plants and of the lower animals; their hypotheses, arguments, and conclusions, do not interfere with our belief that God is to be seen everywhere in his works and rules over all." It appears to me that the whole doctrine of vegetable and animal species needs to be reviewed and readjusted—and religion need not fear the result. I have been convinced of this ever since I learned, when I was ardently studying botany, that the number of species of plants had risen to two millions! I was sure that all these are works of God; but I was not sure that each was a special creation.
When a new truth is discovered, especially when it is a reaction against an old theory, it is apt to bulk so largely in the view of those who hold it that they carry it to extreme lengths, and it requires time and discussion to confine it to its own place. Thus, in old time, Thales perceiving how much water could do, and' Anaximenes how much air could accomplish, and Pythagoras how much numbers and forms could account for, hastened to the conclusion that the whole operations of Nature could be derived from them and explained by them. I am old enough to remember that the brilliant discoveries of