74 Dr. A. Harden and Mrs. D. Norris. Production of [Jan. 25, 



the yield of earbinol may be increased by aerobic culture. The whole of 

 Pore's experiments were carried out under aerobic conditions, and although 

 he employed different organisms from those given above, they have all been 

 shown by Desmots (7) to be capable of producing acetylmethylcarbinol 

 under suitable circumstances. Desmots, in fact, describes experiments very 

 similar to those carried out by Pere\ but makes no mention of the possible 

 formation of glyceraldehyde. It seems therefore not at all unlikely that 

 Pdre^s volatile reducing substance was acetylmethylcarbinol and not glycer- 

 aldehyde. His experiments have accordingly been repeated, using identical 

 culture media and conditions of growth, and the results of these investiga- 

 tions form the subject of the present communication. In addition to 

 repeating Pere's experiments a quantitative estimation of the action, of 

 B. lactis aerogenes on glycerol has been made. In this case neither acetyl- 

 methylcarbinol nor glyceraldehyde is obtained. 



Action o/B. subtilis and B. mesentericus vulgatus on Mannitol and Tyrothrix 

 tenuis on Glucose. 



The culture media were made up exactly in the same way as those used by 

 Pere\ and in the case of the first two organisms named consisted of 20 grin, 

 of mannitol in 200 c.c. water containing 2 grm. ammonium phosphate, 1 grm. 

 ammonium sulphate, and - 4 grm. potassium phosphate. Por the experiment 

 with Tyrothrix tenuis 5 grm. of glucose were made up to 100 c.c. with broth. 

 After sterilisation and inoculation with the organism in question, the various 

 culture media were incubated at 37° C. In every case growth was continued 

 for 30 days, after which time the cultures were worked up according to 

 Perm's directions. To take one example — the action of B. subtilis on mannitol — 

 after the 30 clays' incubation the culture medium was made acid with citric 

 acid and distilled, the distillate was found to be strongly reducing and 

 laevo-rotatory, and also gave a very strong Voges and Proskauer reaction, 

 which is characteristic of acetylmethylcarbinol, but is not given by glycer- 

 aldehyde. The remaining distillate was then made alkaline and again 

 distilled, yielding a second time a reducing lsevo-rotatory body giving the 

 Voges and Proskauer reaction. This second distillate was then steam-distilled 

 for three hours, and by the end of that time the whole of the reducing body 

 had passed over with the steam, the residue being non-reducing and optically 

 inactive. The steam distillate, on the other hand, was still Isevo-rotatory, 

 reducing, and gave the Voges and Proskauer reaction. An osazone was 

 prepared from this distillate and gave a definite melting point of 243° 0.,. 

 corresponding to the phenylosazone of diacetyl, which is always obtained 

 from acetylmethylcarbinol in this manner. In a similar way the action of.' 



