The view is generally held that the intestinal contents in typhoid fever are swarming with typhoid bacilli. The fact that many investigators have often had difficulty in isolating Bacillus typhosus from the stools of undoubted cases of typhoid fever has been attributed to imperfect technical methods. Some observations made by one of us seemed to indicate that the reason typhoid bacilli were not obtained from the stools during the height of the disease might be due, not to faulty bacteriologic methods, but to the fact that the typhoid micro-organisms were either absent from the feces or present in extremely small numbers.
The studies here presented extend over two years. About 75 per cent. of the patients had fever at the time of the examination. All were clinically typhoid fever. In only one instance was the agglutination test persistently negative. It is probable that this was a case of infection with