EXPERIMENT STATION BULLETINS. 507 



TABLE XXVI. — Comparative Germicidal Poicer of Varying Amounts of Lactic Acid. 



♦Less than 50<J0 typhoid bacteria introduced into each cc. of the filtrate. 



OBSERVATIONS. 



1. The tyi)ical lactic organism, liact. laetis acidi (from sonr milk) 

 produces an acid which is iiihibitive to B. ti/phosiis in smaller quantities 

 than the acid produc ed by any other of the above organisms. The mini- 

 mum acidity recorded wliich destroys B. ti/pliosiis is 37°, or 0.3-]- per 

 cent lactic acid. 



2. The a.cid produced by Bacf. laetis acidi 53 P>2, and Bacf. huhjaricani 

 reaches nearly twice 0.3 i)er cent before it is cai)able of destroying- B. 

 ijjplwsus. 



3. The lactic, Bact. laetis acidi (from starter) and the gas producer, 

 Bad. acidi lactici No. 2 have a very uncertain inhibitive effect probably 

 due to their failure to jn'oduce suflicieut acid. 



The acid produced by the most typical lactic organism is Ihe most 

 effective germicide for B. typJwsns in lactose broth. 



