Abstract
1. An outbreak of gastro-enteritis in hospital due to Salmonella derby is described.2. The probable pathways of infection are indicated diagrammatically (Text-fig. 2).3. Attention is drawn to the importance of dust as an environmental source of infection in gastroenteritis in a closed community.4. Methods of control including the detection of carriers, the avoidance of contact with anything that goes into an infant's mouth and the protection of exposed food from dust contamination are stressed.