Mycoplasmas were detected in the external ear canal of goats by swabbing and culture. Up to 10(8) colony forming units were recovered from single swabs. The resulting cultures were usually mixtures of mycoplasmas containing up to 5 species. The species present in sequential swabs varied. Pathogenic species (M.agalactiae, M.capricolum, M.mycoides subsp. capri, M.mycoides subsp. mycoides of the large colony (LC) type, M.putrefaciens) were isolated from the ears and in addition 3 untyped mycoplasmas G, U and V were often present. The same mycoplasmas were found in large numbers in the mites Psoroptes cuniculi and Raillietia caprae which were sometimes present in the external ear canal. The role of the mycoplasmas in the external ear canal as a source of infection and disease and of the mites in the spread of infection requires further elucidation.

Summary Ninety‐three mycoplasmas isolated in Australia from various pathological conditions in cattle and from healthy cattle were classified using the growth inhibition reaction. Eighty strains were placed in seven of the eight groups described by Leach (1967). The number of additional groups into which the 13 remaining strains may fall is not known. Cross‐reactions not described previously were found between M. bovigenitalium and strains of group 7 (L2917).

PLATE LXXXII KUROTCHKIN (1937-38) and others have reported the formation of polysaccharide by Mycoplasma mycoides. Buttery and Plackett (1960) isolated, from washed organisms, a haptenic polysaccharide in a state of relative purity and characterised it as a galactan. Immunodiffusion studies (Plackett, Buttery and Cottew, 1963) revealed the presence in such preparations of several minor components in addition to the main component (P).Large amounts of polysaccharide were found also in culture media after growth of the organisms. A method for the recovery of this material from culture supernatants has been devised. The product behaves like P in serological tests, only a trace of a single minor component being detectable by immunodiffusion. For simplicity, we shall refer to galactan prepared from culture supernatant as galactan F, and to that prepared from washed ceUs as galactan C. Although P is the main component of both kinds of preparation, galactan C contains relatively more of the minor antigenic components detectable by immunodiffusion, whilst galactan F contains some non-specific material derived from constituents of the medium (Buttery, unpublished).During the acute phase of contagious bovine pleuropneumonia, component P is often present in the blood at concentrations high enough to cause the '' eclipse " of agglutination reactions, as described by Turner (1962). Galactan and other antigens, as yet unidentified, were found in body fluids and in urine by Gourlay (1962Gourlay ( , 1964. Two mycoplasms, L2917 and N29, isolated from cases of bovine arthritis, produce a different polysaccharide, a glucan (Plackett et a[.), which also may appear in the blood during infection. This paper describes some of the consequences of the parenteral injection of galactan F into cattle and rabbits, and, in particular, the effect that it has on the course of an infection produced by the subcutaneous inoculation of Mycoplasma mycoides. Some observations with glucan prepared from a culture of mycoplasm L2917 are included for comparison. MATERIALS AND METHODS Strains of mycoplasmIn this work, two strains of Mycoplasma mycoides and a mycoplasm isolated in Queensland from cattle affected with arthritis, and referred to as L2917, were used.The strains of M. mycoides were VS, of a virulence usually sufficient to provoke some local swelling when injected subcutaneously into susceptible cattle, and KH3J, a strain of African origin so low in virulence that no such local swelling is produced (Hudson, 1965). J. PATH. BACT.-VOL. 94 (1967) 257 258 J. R. HUDSON, S. BUTTERY A N D G. S. COTTEW Preparation of galactan F and glucan Cultures of mycoplasms grown in 1 5-litre batches of supplemented BVF-OS medium (Plackett et al.) were centrifuged in a steam-driven Sharples supercentrifuge.The supernatant was heated at 100°C for 45 min., 150 ml. glacial acetic acid was added to bring the pH to 5.5, and heating at 100°C was continued for 45 min. The mixture was filtered and 2 volumes of ethanol were added to the filtrate. The resulting precipit...