Stability of Pleuropneumonialike

The increased significance of pleuropneumonialike organisms has spurred many laboratories to engage in programs relating these organisms to both human and animal diseases. This has resulted in the need for mass production of antigens for diagnostic purposes and in the need for maintenance of rather extensive stock culture collections. Problems of handling encountered in such undertakings require a knowledge of the effects of physical factors on the viability of these organisms. NNo quantitative information has been published concerning the effects of physical environment on survival of pleuropneumonialike organisms. Several reports have been published showing qualitatively that 50 per cent glycerol is not particularly deleterious to rat strains (Beeuwkes and Collier, 1942; Findlay et al., 1939; Woglom and Warren, 1938a, b), murine strains (Sabin, 1938; Edward, 1940), and porcine strains (Switzer, 1954) and that the organisms vary in their resistance to temperatures above 37 C but survive for weeks at refrigerator temperatures (Sabin, 1938; Switzer, 1954; Bridre and Donatien, 1925; Edward, 1940; Findlay et al., 1939; Warren and Sabin, 1942; Woglom and Warren, 1938a, b). In the course of experimentation on the nutrition and metabolism of these organisms, it became necessarv to obtain quantitative information to facilitate the handling of the resting cell suspensions. The study reported here suggests that pleuropneumonialike organisms are more stable to a variety of physical effects than heretofore has been assumed.