and learning, such as van Swieten of Vienna, James Gregory and William Cullen of Edinburgh, and John Mason Good of London, and an innumerable host of others whose day and night dreams never come to fruition, at least in their day. Other men less ingenious and more practical take them up and make practical application of them. Neither a learned man nor a thinker, nor even an inventor and discoverer is necessarily a great man. He is the greater man who is able to comprehend the meaning and significance of new truths and discoveries and to bring them to fruition. It is rare indeed that an inventor comprehends the significance of his own discovery; and it is as rare that he ever turns it to account, to the benefit of humanity, or to enrich himself. This phenomenon is no less true in the development of medicine than it is in the industrial arts. These reflections have naturally led us to a man of the century of which we are writing, who, by a mere coincidence, discovered a specific for the prevention and cure of small-pox, which had been such a terror in Egypt and Asia since the beginning of the Crusades. This man was not a great man. He possessed neither scholarship nor the faculties equal to become a scholar. He was simply a plodding country doctor, of excellent character and humble abilities, with a mind alert for causes of diseases with which he came in daily contact. Nevertheless, he possessed the powers of observation One and induction and made good use of them. wonders that those powers did not lead him to another induction. Since the cow was the repository of the small-pox virus, changed by her vital alchemy into a less virulent virus, the induction seems logical that she was the original source of the infection-the hostess as one might say-of the human species through their dependence upon her for milk, cream, and butter, etc. Such an induction is rather belated, however. The man to whom we refer was plain EDWARD JENNER This celebrity was born at Berkeley in Gloucestershire, England, in 1749. His father was a clergyman of the Church of England. Young Edward had the advantages of a village school, and later was put under a preceptor for further instruction and to determine what pursuit the boy should follow. His preceptor was not a medical man, but, nevertheless, young Jenner drifted into medicine without the advantages of a college education. At that time scholarship was not needed as a necessary precedent for the practice of medicine. A license to practise was the only requisite. Physicians thus qualified were called licentiates of this or that college or medical society. So far as we know, this was Jenner's only authority to practise. However that may have been with Jenner, an inkling of his discovery dawned upon him while with his preceptor in Gloucestershire. It happened to be a dairy country, and small-pox was rife thereabouts as elsewhere in Europe. It appears that a country woman called upon his preceptor on one occasion for advice, and remarked to him that she could not take small-pox for the reason that she had had cow-pox. It was a tradition in the country there that one who had taken the cow-pox could not take the small-pox -that which was popularly known to them as cow-pox rendered them immune to small-pox, a similar malady, but far less terrible in its results, when not fatal. The dairy-maids were usually exempt from the disease. Not long after this circumstance Jenner went to London to perfect his medical studies, and while there talked over the subject that had been uppermost in his mind with the celebrated anatomist, John Hunter. This was in the year 1770. Dr. Hunter, when asked what he thought of the possibility of the virus of cow-pox taking the place of inoculation with the virus of small-pox, bluntly advised young Jenner "to try it." Two or three years later Jenner returned to his native town, Berkeley, and set himself up as a surgeon. The dream of substituting vaccination in place of inoculation continued to haunt his nights and days, and it seems that he then began "to try it," as advised by Dr. Hunter. He confided his secret to a friend, cautioning him not to divulge it; |