Abstract
SUMMARY: Three main antigens were found to be variously distributed amongst strains of Pseudomonas pyocyanea. The serological behaviour of the strains studied depended on the presence and quantity of these antigens. It was not possible to distinguish between flagellar and somatic antigens, but those found were probably somatic.
Amongst the peculiarities of serological behaviour of bacteria in this species the most striking was a complete loss of agglutinability on moderate heating, which left the antigenic activity unimpaired.