160 MAX LEVINE 



hydrates and alcohols. It appears that B. cloacae differs from 

 B. aerogenes by the ability to give the reaction with mannite and 

 galactose while the latter (5". aerogenes) may be distinguished 

 from B. coll by its positive reaction in glucose and saccharose. 

 The differentiation is suggestive and interesting but question- 

 able, since the experimental evidence is inconclusive. 



The term "Voges-Proskauer Reaction" is generally under- 

 stood to mean the production of an eosin-like coloration when 

 a glucose broth culture is made alkaline with potassium hydroxide. 

 To employ the same term when some other carbohydrate is 

 substituted for glucose may lead to confusion. It is therefore, 

 suggested that the term "Voges-Proskauer Reaction" be re- 

 stricted to designate the formation of acetyl-methyl-carbinol 

 from glucose, but when referring to its production from other 

 carbohydrates or alcohols, the term Acetyl-methyl-carhinol 

 Test or merely Carbinol Test be employed. The nature of the 

 substance being tested for is thus indicated just as is the case 

 -with the Indol Test. 



The following experiment was carried out as a preliminary 

 study on the production of acetyl-methyl-carbinol from various 

 substances by coli-like bacteria. Forty-six organisms were 

 selected. Twenty were strains which previous studies had 

 shown did not produce the carbinol from glucose. They repre- 

 sent five sources, horse, sheep, cow, pig and man. From each 

 source a culture representative of each of MacConkey's four 

 groups was included. As far as possible no two cultures were 

 from the same animal. The object of this selection was to 

 obtain a group of Voges-Proskauer negative strains which would 

 be likely to contain many different varieties. 



The other 26 cultures were strains which previous tests had 

 shown could form the carbinol from glucose. These included 

 9 strains isolated from sewage, and 17 strains obtained from 

 Rogers and Kligler. 



The organisms were inoculated into a medium consisting of 

 0.5 per cent di-potassium phosphate 0.5 per cent peptone and 

 0.5 per cent of the test substance. The Digestive Ferments 

 Company peptone was employed for the test with glucose. 



