Again, it is very perplexing to find that the only Tertiary skulls and skeletons for which we possess really strong evidence, those of Castelnedolo, instead of showing, as might be expected, a still more rude and Simian aspect than that of Canstadt, show us the Canstadt type indeed, but in a milder and more human form. All that can be said with certainty is, that as far as authentic evidence carries us back, the ancestral animal, or missing link, has not been discovered, but that man already existed from an enormous antiquity, extending certainly through the Quaternary into the Pliocene, and probably into the Miocene period, and that at the earliest date at which his remains have been found the race was already divided, as at present, into several sharply distinguished types. This leaves the question of man's ultimate origin completely open to speculation, and enables both monogenists and polygenists to contend for their respective views with plausible arguments, and without fear of being refuted by facts. Polygeny, or plural origins, would at first sight seem to be the most plausible theory to account for the great diversities of human races actually existing, and which can be shown to have existed from such an immense antiquity. And this seems to have been the first guess of primitive nations, for most of them considered themselves as autochthonous, sprung from the soil, or created by their own native gods. But by degrees this theory gave place to that of monogeny, which has been for a long while almost universally accepted by the civilized world. The cause of this among Christians, Jews, and Mahometans has been the acceptance of the narratives in Genesis, first of Adam and secondly of Noah, as literally true accounts of events which actually occurred. This is an argument which has completely broken down, and no competent and dispassionate thinker any longer accepts the Hebrew Scriptures as a literal and conclusive authority, on facts of history and science which lie within the domain of human reason. The question, therefore, became once more an open one, but as the old orthodox argument for monogeny faded into oblivion, a new and more powerful one was furnished by the doctrine of Evolution as expounded by Darwin. The same argument applies to man as to the rest of the animal world, that if separate species imply separate creations, these supernatural creations must be multiplied to such an extent as to make them altogether incredible; as for instance 150 separate creations for the land shells alone of one of the group of Madeira islands; while on the other hand genera grade off into species, species into races, and races into varieties, by such insensible degrees, as to establish an irresistible inference that they have all been developed by evolution from common ancestors. No one, I suppose, seriously doubts that this is in the main the true theory of life, though there may still be some uncertainty as to the causes and mode of operation,