Jenner and John Hunter During his training in medicine Dr Edward Jenner was a student of the great London surgeon John Hunter. The two men became the greatest of friends over a period of more than 20 years, until Hunter's death in 1793. They corresponded frequently on matters of medicine and biology. Unfortunately, only Hunter's letters to Jenner survive; these reveal the great range of topics that interested the two men. In their correspondence on hedgehogs during 1775 Hunter urged Jenner to follow a policy which shaped his attitude to research: "I thank you for your Expt on the Hedge Hog, but why do you ask me a question, by the way of solving it. I think your solution is just; but why think, why not trie the Expt." Hibernation Because Hunter lived most of his life in cities, their collaboration in the study of hibernation fell mostly to Jenner, the country dweller. They were intrigued by the way certain plants and animals could suspend their life processes during the winter. Hunter encouraged Edward Jenner to cut into the bark of trees during the winter, to discover whether the sap continued to flow. Jenner also measured the body temperature of hedgehogs through the changing seasons. He used a precious thermometer that had been given to him by John Hunter. When his first thermometer was accidentally broken after five years of use his friend sent a replacement. The letter accompanying it gently told him off for being clumsy. Other experiments involved placing food in the stomach of hibernating hedgehogs, then observing whether it was digested. They also researched the body temperatures of bats, dogs and birds, as well as the temperature changes in inflamed tissues. Bird Migration This interest in hibernation was also linked with another topic that occupied Edward Jenner: bird migration. It was commonly assumed that birds hibernated in river mud when they disappeared in the winter. Jenner was one of the first to comment that when birds first appeared in the spring they were neither starving nor dirty. He examined the contents of their stomachs, looking for signs of a recent meal. He also noted reports that these birds were sometimes seen flying far out across the oceans. Jenner speculated that the birds left the British Isles through the winter, returning the next summer. In 1787 Jenner wrote to another of his close friends, the famous botanist Joseph Banks who sailed on Captain Cook's voyages to the Pacific Ocean, promising a report on these ideas and observations on bird migration. Unfortunately, Jenner never did find the time to write up his studies, but his family published them after his death. Design by Actis Limited Return to top of page