ANTI-ENZYME IMMUNITY 261 



papain, digested raw muscle, but were inactive against raw egg al- 

 bumin and serum; in this respect, they behaved like trypsin. Like 

 trypsin, they were active in neutral or weakly alkaline medium. Co- 

 agulated albumins were hydrolyzed to amino acids. Like trypsin, the 

 bacterial proteinases were precipitated from their solutions by 0.8 

 per cent safranin. 



The hydrolysis of gelatin by CI. Sforogenes proteinase was inhibited 

 by 0.1 ml. of normal horse serum, which was evidently due to the 

 trypsin inhibitor normally present in the serum. In contrast, as much 

 as 1 ml. of normal horse serum had no inhibitory action on the pro- 

 teinase activity of CI. histolyticum. This highly active digestive prop- 

 erty of the latter bacterium was assumed to be responsible for the tissue 

 damage caused in an infected host when a culture of this bacillus 

 is injected into the muscle of a guinea pig. 



The gelatinase activity of CI. sforogenes was inhibited in the pres- 

 ence of raw egg white but that of CI. histolyticum was not at all af- 

 fected (Pozerski and Guelin, 1938a). 



Horses immunized (M. Weinberg) with the filtrates of CI. his- 

 tolyticum and CI. Sforogenes yielded specific antisera. The proteinase 

 activity of CI. sforogenes was not inhibited at all by the antiproteinase 

 immune serum against CI. histolyticum. and vice versa. 



Pozerski and Guelin (1938b) also studied the proteolytic activity 

 of thirteen anaerobic bacilli from M. Weinberg's collection at the 

 Pasteur Institute, Paris. Of these, only three failed to show any activity; 

 the other ten anaerobes manifested proteolytic activity of varying 

 intensity. Proteolytic preparations from CI. histolyticum,, vihrion sef- 

 tique and CI. ferfringens (welchii~) D, B and C manifested escha- 

 rotic properties when injected subcutaneously into guinea pigs. A 

 similar property with the proteolytic filtrates of the other bacilli was 

 not obtained. 



Smith and Lindsley (1939) studied the proteolytic activity of bac- 

 teria of the gas-gangrene group which cause much tissue damage. 

 They compared the proteolytic activity of pathogenic and non-patho- 

 genic members of this group. In this study, similar in many respects 

 to that by Blanc and Pozerski (1920) and Maschmann (1937), they 

 found that normal serum inhibited a proteolytic enzyme found in 

 non-pathogens, but the activity of the pathogens was not inhibited. 

 Of the pathogens tested, CI. histolyticum, CI. welchii, and CI. oede- 



