The dysgonic form of Microsporum canis in N.W. London.

An account is given of the occurrence in N.W. London of ringworm due to the dysgonic form of Microsporum canis in cats, dogs, and humans. The unusual morphology of the dysgonic strain is described as is the extraordinary lability of the fungus in culture. The distribution of cases in man and animals in the area is mapped. The clinical and epidemiological behaviour of the fungus, as illustrated by four family outbreaks, differs little from that of the typical strain. The origin of the dysgonic strain is unknown.