1. A description is given of a weakly haemolytic organism, which first appeared as a contaminant, in the form of pin-point colonies, in agar plates inoculated with dilutions of a cream which had been subjected to partial processing in a butter churn.

2. Though it resembled in many respects certain strains of Str. bovis recently isolated from pasteurized milk in America, it is concluded that the majority of its characteristics showed it to be a resistant strain of Str. thermophilus which had adapted itself to contaminate a churn.

3. That the churn was responsible for the spread and maintenance of this heat resistant contaminant is regarded as significant and indicates that efficient pasteurization must be followed by storing and processing in sanitary equipment.

I am indebted to Dr M. Grimes for his help and suggestions in the course of this work.