Sir: I can match the anecdote related by my friend Owen Wells (Letters, 28 January). In July 1960, as leader of an expedition in East Greenland, I visited one of our high camps with our medical officer, David Jones. At the camp, one of my companions was suffering from a carbuncle in his neck. Dr Jones took out his Swiss penknife, with which he and I had been eating sardines on our way up the glacier, and performed a successful, if painful, operation. I was thankful not to be the patient who, however, has cause to be grateful to the Swiss Army - and, of course, to David.