Published online by Cambridge University Press: 15 May 2009
1. It has been found possible to detect traces of the virus of foot-and-mouth disease in mixtures of this virus and that of vesicular stomatitis by cross-immunity tests in cattle. A quantity of the virus of foot-and-mouth disease as small as 1·3 I.D. 50 was revealed by the inoculation of such mixtures into cattle immune to vesicular stomatitis.
2. It is suggested that such a method would be useful in the analysis of possible mixed infections in field outbreaks.
3. The usefulness of complement-fixation tests to confirm the resolution of mixtures has been demonstrated.
The author wishes to thank the Director of this Institute, Dr I. A. Galloway, for his advice and encouragement. The technical assistance of Messrs E. Scoates and P. M. Mitchell is also gratefully acknowledged.