3 66 THE POPULAR SCIENCE MONTHLY. 



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 valua- 

 ble 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. Jen- 

 ner, 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 con- 

 tracted cow-pox from the cows would never have smallpox. The 

 thought came to him, Can this virus ~be inserted voluntarily in the 

 human subject 9 He mentioned his speculations on the subject, 

 that was even then taking a firm hold on his mind and inexorably 

 marking out his role in life, to Hunter, who listened with interest, 

 thought they were " curious," but was too .much absorbed by his 

 bwn engrossing themes to more than repeat his famous instruc- 

 tion, " Don't think, but try/' That the new idea in biological sci- 

 ence that was to rescue millions from premature graves came to a 

 trained intelligence is further shown by the fact that, while Hun- 

 ter's pupil, Jenner had been employed to prepare and arrange the 

 valuable zoological 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 dis- 

 cussed 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- 



