Thus in the nature of Christianity, as a miraculously founded and revealed religion, lay the ground for expecting miracles, or, at least, for not deeming them unlikely to occur. And to the same result from all sides conspired the influences which had been obscuring natural knowledge. We have followed those influences in pagan circles from Plato on through Neo-Platonism and other systems current in the first centuries of the Christian era. We have seen them obliterate rational conceptions of nature’s processes and destroy the interest that impels to unbiassed investigation. The character and exigencies of the Faith intensified the operation of like tendencies among Christians. Their eyes were lifted from the earth. They were not concerned with its transitory things, soon to be consumed. Their hope was fixed in the assurance of their Faith; their minds were set upon its confirmation. They and their Faith seemed to have no use for a knowledge of earth’s phenomena save as bearing illustrative or confirmatory testimony to the truth of Scripture. Moreover, the militant exigencies of their situation made them set excessive store on the miraculous foundation and continuing confirmation of their religion. For these reasons the eyes of the Fathers were closed to the natural world, or at least their vision was affected with an obliquity parallel to the needs of doctrine. Any veritable physical or natural knowledge rapidly dwindled among them. What remained continued to exist because explanatory of Scripture and illustrative of spiritual allegories. To such an intellectual temper nothing seems impossible, provided it accord, or can be interpreted to accord, with doctrines elicited from Scripture. Soon there will cease to exist any natural knowledge sufficient to distinguish the normal and possible from the impossible and miraculous. One may recall how little knowledge of the physiology and habits of animals was shown in Pliny’s _Natural History_.[78] He had not even a rough idea of what was physiologically possible. Personally, he may or may not have believed that the bowels of the field-mouse increase in number with the waxing of the moon; but he had no sufficiently clear appreciation of the causes and relations of natural phenomena to know that such an idea was absurd. It was almost an accident, whether he believed it or not. It is safe to say that neither Ambrose nor Jerome nor Augustine had any clearer understanding of such things than Pliny. They had read far less about them, and knew less than he. Pliny, at all events, had no motive for understanding or presenting natural facts in any other way than as he had read or been told about them, or perhaps had noticed for himself. Augustine and Ambrose had a motive. Their sole interest in natural fact lay in its confirmatory evidence of Scriptural truth. They were constantly impelled to understand facts in conformity with their understanding of Scripture, and to accept or deny accordingly.