Leptospires are difficult to stain with the usual bacterial stains; many different stains have been proposed, most of which are designed for staining of tissue sections. Silver stains that are available for smear preparations yield variable, unreliable

A technique for leptospiral lipase extraction which yielded a highly active, stable, and concentrated lipase preparation was developed. The chief characteristics of leptospiral lipase were determined and are summarized below. Leptospiral lipase was soluble in water and stable in both the dry state

Summary A number of methods advocated for the isolation of ‘bacteroides’ have been tested. By using an ethyl violet–azide agar medium under strictly anaerobic conditions, as many as 108/g of a group of obligately anaerobic Gram‐negative bacteria were detected in the caeca of chickens. Freshly isolated organisms from chlortetracycline fed chickens showed a slightly greater resistance to chlortetracycline than those isolated from the control birds, but there was little difference after further subculture.

SUMMARYA comparison, by numerical taxonomy methods, was made of 72 named or freshly isolated strains of Gram-negative anaerobes which were considered to belong within the family Bacteroidaceae. In the first analysis 57 strains were compared. Representative strains were then selected and compared with additional named strains in a second analysis. Four phena were identified : (I) strains of Sphaerophorus, Fusobacterium and Bacteroides melaninogenicus, (2) Bacteroides, (3) unnamed poultry isolates, (4) a second group of unnamed poultry isolates. The most useful differential tests were found to be : (a) cell morphology, (b) the terminal pH value in glucose broth and the production of formic, acetic, propionic or butyric acids, (c) the production of propionic acid from threonine, ( d ) growth stimulation by bile, (e) the effect of various inhibitors.