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acib jTucbeine ae ata Hgcnt for tbe 

 2)i0tinctton of ffiacterta/' 



IN the Abstract of Sanitary Reports for August 23rd, 1895, 

 Dr. E. Andrade Penny, assistant in the Hygienic Laboratory 

 of the Marine-Hospital Service, has an article which is 

 substantially as follows : 



The changes of reaction brought about by different kinds of 

 bacteria in the culture media where they are grown have not been 

 carefully studied. There exists considerable variance of opinion 

 among bacteriologists as to the reactions of the intestinal micro- 

 organisms, more especially the Bacillus typhosus and the Bacillus 

 coli communis. Brieger holds that the Bacillus typhosus produces 

 an acid change. Klemensciewicz states that both these produce 

 an acid reaction, which is more marked in the Bacillus coli. 

 Thoinot and Masselin, on the other hand, say that, according to 

 their experience, the Bacillus coli communis produces first an 

 alkaline reaction, which gradually changes into an acid. Pere, 

 after a careful investigation, states that in peptone bouillon made 

 from meat less than forty hours old both the Bacillus coli communis 

 and the Bacillus typhosus produce an acid which gradually changes 

 to an alkali, the stages of acidity being shorter with the Bacillus 

 typhosus than with the Bacillus coli. These reactions varied 

 according to the time the meat was kept before use. Pere con- 

 cludes that the different and opposite results of the investigators 

 are due to the influence of the variable composition of the media, 

 and not so much to the micro-organisms in question. 



In view of these contradictory statements, the author says, 

 and believing that very important and useful data for distinguish- 

 ing bacteria and for the complete knowledge of their biological 

 properties could be obtained from the careful study of the reactions 

 they produce in different culture media, he has undertaken a series 

 of experiments. The results obtained deal with those forms of 

 bacilli which are usually found in the intestinal canal — viz., the 

 Bacillus coli communis^ the Bacillus typhosus^ the Bacillus proteus 

 vulgaris., the Bacillus acidi lactici^ and the Bacillus lactis aerogenes. 

 * From The New York Medical Journal. 



