This evidence, better than any secondary description, will enable the reader to appreciate the prevalent furore as it affected the leaders of the medical world. At the same time it is to be borne in mind that the craze was superficial. Any radical change in conviction or practice is never accomplished thus easily or thus rapidly. The medical men who bore witness for cowpox had been bred to inoculation with smallpox, for which cowpox was substituted. The change was essentially trivial. The trouble, the danger, and the uncertainty of variolous inoculation were generally recognised, and when cowpox was recommended as a mild form of smallpox, it was not difficult to appreciate the asserted advantage: for, as it was argued, no one can have smallpox twice, and as the mildest attack of smallpox is as prohibitive of a second attack as the severest, therefore cowpox (which is smallpox in mild form) must protect as effectually when inoculated. With logic so admirable, it was in nowise wonderful that so many were carried away; but unfortunately, as so often happens, matter-of-fact did not correspond to the admirable logic. The DUKE OF CLARENCE testified that he had availed himself of Jenner’s discovery from the outset. His children, his household and farm servants were all protected. A postillion positively refused to be operated on, and eighteen months after he caught smallpox in the most virulent form. Children who had undergone cowpox were constantly in the room where the lad lay and suffered no harm. The EARL OF BERKELEY had his son inoculated with cowpox by Dr. Jenner at the age of six months. One of his maid-servants took smallpox and died, and the effluvia during her illness was so offensive that his servants had to move to another part of the house. To test the reality of his son’s protection, he sent for Jenner, and got him to inoculate the boy with pox from the maid. The child was found to be proof, for the inoculation had no effect--To illustrate the validity of the Gloucestershire tradition, he related how a man of 72 in his service had caught cowpox when a boy of 15 whilst milking, and in consequence always reckoned himself secure from smallpox, exposing himself to the disease with complete indifference. LORD ROUS gave similar evidence. His child had been inoculated with cowpox at the age of three months, and he was perfectly satisfied that he could never have smallpox.