424 



On Voges and Proskauer 's Reaction for Certain Bacteria. 

 By Arthur Harden, D.Sc, Ph.D. 



(Communicated by Dr. C. J. Martin, F.R.S. Received December 5, 1905, — 

 Read February 1, 1906.) 



(From the Chemical Laboratory Lister Institute.) 



In 1898 Voges and Proskauer* described a new colour reaction which 

 they had observed in the case of a bacillus, isolated by Voges and grown in 

 a medium containing sugar. When potash was added and the tube allowed 

 to stand for 24 hours or longer at room temperature, a beautiful fluorescent 

 colour, somewhat similar to that of a dilute alcoholic solution of eosin, 

 formed in the culture fluid, particularly at the open end of the tube exposed 

 to the air. The reaction was found to be specific to the bacillus in question, 

 and was not given by any of the other organisms isolated in the course of 

 the investigation upon which they were engaged, nor by the B. coli 

 communis, so that it afforded a. most valuable means of differentiation for 

 the inhabitants of the intestine. Durhamf and HowJ have also employed 

 this reaction for the discrimination of intestinal bacteria, and MacConkey,§ 

 in confirmation of Durham, has found that out of a large number of bacteria 

 which were tested only three gave the reaction, these being B. lactis aerogenes 

 (Escherieh), B. capsulatus (Pfeiffer), and B. cloacce (Jordan). 



The examination of the products formed by B. lactis cteroyenes from 

 glucose|| has shown that acetylmethylcarbinol, CH 3 .CO.CH(OH).CH 3 , and 

 2-3-butyleneglycol, CH 3 .CH(OH).CH(OH).CH 3 , are both present in the 

 medium in which this has been cultivated in the presence of glucose. The 

 acetylmethylcarbinol has not as yet been isolated in the pure state, but 

 is present in the aqueous distillate obtained by distilling the culture medium. 

 This distillate and the glycol were, therefore, treated with caustic potash in 

 order to ascertain whether either of them was the cause of the reaction 

 just described. Neither of these substances produces the characteristic 

 fluorescent coloration with potash alone, but when peptone water is also 

 added, acetylmethylcarbinol gives the reaction after standing for about 

 24 hours, whilst the glycol does not react in this way even on standing. 

 The coloration was produced in the characteristic manner described by 



* ' Zeitschr. f. Hyg.,' 1898, vol. 28, p. 20. 



t ' Journ. of Experimental Medicine,' 1900 — 1901, p. 354. 



\ 'Centralbl. f. Bakter.,' 1904, vol. 36, p. 484. 



§ ' Journ. of Hyg.,' 1905, vol. 5, 349. 



t| Harden and Walpole. 



