494 Dr. A. Harden and Mrs. D. Norris. Production of [Nov. 22, 



Among the products of the reaction, acetylmethylcarbinol and butylene 

 glycol only have been estimated quantitatively. A more complete investiga- 

 tion has, however, been made in the case of glycerol, and the results 

 obtained will form the subject of another communication. 



To ascertain whether the carbinol and glycol were derived from the 

 acetaldehyde, sugar or other substances in question, and not simply from 

 a constituent of the peptone, control experiments were carried out with 

 peptone water alone as culture medium. In no case could the slightest trace 

 of either substance be detected. 



2. Detection and Estimation of Acetylmethylcarbinol and Butylene Glycol. 



As some of the substances employed could only be used in small 

 quantities, it was necessary to elaborate a method for the detection of both 

 acetylmethylcarbinol and butylene glycol in small amounts. Attempts were 

 first made to separate these two compounds by cautious evaporation and 

 estimate them individually, but it was found impossible to arrive at any 

 quantitative values in this way. 



The method ultimately adopted was as follows : — 



The medium in which the organism had been grown was carefully 

 distilled to as small a bulk as possible over a free flame and then to dryness 

 under reduced pressure at 37° C. The distillates were then united and made 

 up to a definite volume and portions tested for reducing power and for 

 Voges and Proskauer's reaction, which, as stated above, is due to the 

 presence of acetylmethylcarbinol. To perform this reaction 3 c.c. of 1 per 

 cent. Witte's peptone water are mixed in a test-tube with an equal quantity 

 of 10 per cent, caustic soda, 2 c.c. of the solution to be tested are then 

 carefully poured on to the surface of the liquid, and the tube is allowed to 

 stand at room temperature. If acetylmethylcarbinol be present, a pink ring 

 forms at the juncture of the two liquids. With very small quantities of 

 carbinol, this may take some hours to develop, but with larger amounts the 

 colour soon appears and quickly spreads through the whole of the solution, 

 a green fluorescence being also produced. It was found that more delicate 

 results could be obtained by the above method than by simply mixing the 

 solutions. 



Experiments in connection with other work, shortly to be published, have 

 indicated that the carbinol is alone responsible for the reducing power of 

 the distillates, and hence an estimation of this by Baug's (11) method at 

 once gives the amount of acetylmethylcarbinol present, the reducing power 

 of this substance being known (12). 



The estimation of the butylene glycol is not such a simple matter. 



