a1 Enteric Reference Laboratory, Public Health Laboratory Service, Colindale Avenue, London, NW 9 5 HT, England
The phage-typing scheme of Callow (1959) has been extended. The original number of types was 34; this has now risen to 207. Tables are presented which show the provisional type designations and the definitive designations now being introduced.
(Received November 22 1976)
* Requests for reprints to: Professor E. S. Anderson, Enteric Reference Laboratory. Colindale Avenue, London NW9 5HT.