death, was thirteen years old, but he already had evinced a strong taste for natural history—had begun an orderly and well-kept cabinet of new and original specimens, and had formed the valuable habit of recording in a note-book his observations on physical phenomena. His father had died when he was six years old, but he was reared with great care and tenderness by an elder brother, who, perceiving his strong natural bent, apprenticed him to a surgeon, with whom he diligently studied and worked till he was twenty-one, when he went to London to become the pupil of the celebrated John Hunter, in whose family he lived for two years. Hunter had a large private menagerie at Brompton, where he solved for himself some important questions in physiology. Jenner, filled with admiration at the large and unselfish way in which Hunter pursued knowledge for its own sake, formed a friendship for his great master that ceased only at Hunter's death, whose letters to Jenner are among the most interesting extant.
While yet a surgeon's apprentice, before he went to London, he had written in his note-book that he had heard a milkmaid say "she could not have the smallpox as she had had cow-pox"; and the Duchess of Cleveland, when taunted that she might lose her beauty, had replied, "I have no fear of that, for I have had a disease that will save me"; and he was familiar with the general tradition in the dairies of Gloucestershire that those who had contracted cow-pox from the cows would never have smallpox. The thought came to him, Can this virus he inserted voluntarily in the human subject? He mentioned his speculations on the subject, that was even then taking a firm hold on his mind and inexorably marking out his rôle in life, to Hunter, who listened with interest, thought they were "curious," but was too much absorbed by his own engrossing themes to more than repeat his famous instruction, "Don't think, but try." That the new idea in biological science that was to rescue millions from premature graves came to a trained intelligence is further shown by the fact that, while Hunter's pupil, Jenner had been employed to prepare and arrange the valuable zoölogical specimens brought back by Captain Cook's first expedition in 1771, and did the work so acceptably as to be invited to accompany the second expedition as naturalist—an honor which he refused, preferring to return to his country home and engage in the practice of his profession near the brother to whom he was devotedly attached; and those who believe in the "destiny that shapes our ends" will say, where he could study the mysteries of cow-pox in its native haunts. He soon had a large practice, and he formed a society of the medical men of his vicinity they discussed medicine first and dined afterward—Jenner contributing his full share both of the solid work and the fun. Hunter wrote him, "I am very happy that some of you have wished to commu-