It was while the ravages of smallpox were being felt and deplored over the whole country, that Jenner was quietly investigating and experimenting in his native village; and gradually little facts and incidents relating to cowpox were collected, until in his own mind an opinion was firmly rooted that this disease communicated by the cow was a safeguard against smallpox. About the time when he had formed this opinion, an accidental case of cowpox occurred in his neighbourhood, and he caused drawings of the pustules to be made, and took them with him to London. He showed them to some of the most eminent surgeons and physicians of the day, and explained his views; but from none of them did he receive any encouragement, and from some, nothing but ridicule. Fortunately, however, he was not a man to be easily turned aside from a purpose, or disabused of an opinion that he saw good cause for entertaining. On returning home, he was still as full of the idea as ever, and determined to persevere in his efforts; although he saw he must have proofs before he could get his professional brethren to listen to his theories. It was on the 14th May 1796—a day which is still commemorated in Berlin as a festival—that a boy was vaccinated with matter taken from the hands of a milkmaid. The disease was thus communicated to the boy, and he passed through it satisfactorily. But now came the anxious and critical trial for Jenner. The same boy on the 1st of July following was inoculated with the smallpox virus, but he did not take the disease. In 1798 Jenner published his first pamphlet _On the Causes and Effects of Variola Vaccine_; and later, in the first year of the present century, he wrote that it was ‘too manifest to admit of controversy, that the annihilation of the smallpox, the most dreadful scourge of the human species, must be the final result of this practice.’ Soon after this, a parliamentary Committee investigated and reported on the new discovery in terms of the most emphatic approbation; and a declaration was signed by seventy of the chief physicians and surgeons in London expressing their confidence in it. The Royal Jennerian Society was formed, with Jenner as President; and thirteen stations for the vaccination of the public were opened in London, in the hope of exterminating smallpox. Jenner’s essay which explained his discovery had in the meantime been translated into several foreign languages, and had also found its way to America, where President Jefferson vaccinated, by the help of his sons-in-law, about two hundred of his friends and neighbours. From this time forward, vaccination may be said to have taken a firm hold of the civilised world.