Seventy-six cases of dysentery occurring over a period of six months were investigated. B. dysenteriae Flexner was isolated from eleven of these cases and B. dysenteriae Sonne was isolated from fourteen cases. B. dysenteriae Flexner only was isolated from cases occurring among bedridden patients. B. dysenteriae Flexner only was isolated on four occasions from the milk supplied to the hospital. No cases of dysentery occurred among bed-patients after the enforcement of instructions that all milk should be boiled and the stoppage of the supply of cream to the hospital.
Vi agglutination is to date the best serological method for detecting typhoid carriers. The usual technique may present certain difficulties, which are accentuated by South African conditions. These difficulties are largely due to the lengthiness of the usual procedure. This lengthiness causes the serums, which are often not sterile, to decompose and also allows growth of contaminants. Dark-ground studies of Vi agglutination suggested that centrifugalisation would speed up the process by providing just that contact between the bacteria which is the typical pattern of Vi agglutination. In practice it proved possible, by incubating the mixtures of serum and bacteria for a very short time and then centrifugalising them at high speed, to circumvent the difficulties mentioned. This improved technique is descriptionbed in detail.