To the Editor: The present outbreak of typhoid fever in the city of Lima has made it imperative for us to improve the bacteriologic diagnosis of this disease. On the assumption that duodenal secretions might contain appreciable numbers of Salmonella typhi during the illness, we have started sampling these contents with a string-capsule procedure. The sampling period was reduced to three hours, enabling us to include ambulatory patients. We obtained the best results by dropping a 25-cm length of the bile stained string into selenite enrichment broth. This procedure was tested against the highly successful bone-marrow culture and a single blood...