THE VOGES-PROSKAUER REACTION 157 



In order to test further, the correlation between the H+ ion 

 concentration, and acetyl-methyl-carbinol production, 10 or- 

 ganisms which Dr. Khgler had observed to be positive for the 

 Voges-Proskauer reaction were obtained. Two of these failed 

 to form gas from glucose and will not be considered further 

 here. The remaining eight strains were alkaline to methyl 

 red and gave a positive Voges-Proskauer test. 



Thirteen organisms were also obtained from L. A. Rogers. 

 Five were acid to methyl red and gave a negative Voges.-Pros- 

 kauer test. One failed to grow at 37°C. All of the others 

 (7) were alkaline to methyl red and gave a positive reaction 

 when tested for the formation of acetyl-methyl-carbinol in glu- 

 cose-peptone solution. 



The high correlation between the Voges-Proskauer reaction 

 and the indicator test of Clark and Lubs makes it possible to 

 compare the work of Rogers and his associates with that of 

 previous investigators. Such a comparison shows a striking 

 unanimity of opinion as to the significance of these reactions, 

 Rogers regards the high gas ratio and alkalinity to methyl red 

 as characteristic of B. aerogenes-\ike bacteria. Practically all 

 who have employed the Voges-Proskauer reaction have pointed 

 out that this test is characteristic of B. aerogenes and B. cloacae. 

 Of a large number of coli-like strains examined by MacConkey 

 in 1905, only three B. aerogenes Escherich B. copsulatus Pfeiffer 

 and B. cloacae Jordan gave the Voges-Proskauer reaction. Dur- 

 ham in 1901 observed that this test was given only by those 

 organisms which he regarded as belonging to the B. aerogenes 

 group. 



THE DISTRIBUTION OF COLI-LIKE ORGANISMS WHICH GIVE A 

 POSITIVE VOGES-PROSKAUER REACTION 



Coli-like organisms which form acetyl-methyl-carbinol in 

 glucose peptone solution are rarely found in feces. A reasonably 

 accurate and reliable idea as to the distribution of such bacteria 

 in nature may be obtained from a study of the distribution of 

 B. aerogenes and B. cloacae. 



