3.

The eminent physician of our own times, Vindicianus, being consulted by an invalid, prescribed for his disease what seemed to him a suitable remedy at that time; health was restored by its use. Some years afterwards, finding himself troubled again with the same disorder, the patient supposed that the same remedy should be applied; but its application made his illness worse. In astonishment, he again returns to the physician, and tells him what had happened; whereupon he, being a man of very quick penetration, answered: "The reason of your having been harmed by this application is, that I did not order it;" upon which all who heard the remark and did not know the man supposed that he was trusting not in the art of medicine, but in some forbidden supernatural power. When he was afterwards questioned by some who were amazed at his words, he explained what they had not understood, namely, that he would not have prescribed the same remedy to the patient at the age which he had now attained. While, therefore, the principle and methods of art remain unchanged, the change which, in accordance with them, may be made necessary by the difference of times is very great.