1912.] Acetylmethylcarbinol and 2.3-Butylene Glycol. 75> 



B. mesentericus vulgatus and Tyrothrix tenuis on mannitol and glucose respec- 

 tively was also examined and similar results obtained. 



The Action of Tyrothrix tenuis on Glycerol. 

 This offered a case of much greater interest, as the formation of 

 acetylmethylcarbinol would involve a carbon synthesis, and does not take 

 place from this substance when B. lactis aerogenes is used under anaerobic 

 conditions. 



Pe^'s directions were again carefully followed, 5 grm. of glycerol were 

 made up to 100° C. with broth, and, after sterilisation and subsequent 

 inoculation, were incubated at 37° C. for 30 days. An investigation of the 

 culture medium, as described above, again showed the presence of acetyl- 

 methylcarbinol, which passed over into the distillate, and was characterised 

 by the preparation and analysis of the osazone, as well as by the Voges and 

 Proskauer reaction. The lead, calcium, and barium salts of the oxidation 

 products analysed by Pere\ and believed by him to be the salts of glyceric 

 acid, were in all probability the salts of lactic acid. As he was only able to 

 analyse extremely small quantities (O032 grm. of a lead salt containing 

 50 per cent. Pb) of non-crystalline substances, the experimental error was 

 probably too great for him to distinguish between these two acids. There is 

 therefore no evidence to show that glyceraldehyde is produced in the 

 above fermentations, and the theory that sugars undergoing bacterial 

 fermentation are first broken down to trioses derives no support from this 

 investigation. 



The Action of B. lactis aerogenes (Bschcrich) on Glycerol under Anaerobic 

 Conditions. 



The experiments previously described were all carried out under aerobic 

 conditions, and, as an example of anaerobic decomposition, the action of 

 B. lactis aerogenes on glycerol has been studied. This organism under these 

 conditions forms acetylmethylcarbinol from all the hexoses, but produces 

 none from glycerol, no reducing substance at all being found among the 

 products of the reaction. 



The method of investigation was substantially that used by Harden (8), the 

 gases, however, being collected and measured in the apparatus devised by 

 Harden, Thompson, and Young (9). The organism was grown in an 

 atmosphere of nitrogen, the medium consisting of 1 per cent. Witte's 

 peptone solution containing 10 per cent, of glycerol, sufficient chalk being 

 added to neutralise the acids formed during fermentation. In the glycerol 

 experiments quoted, the times of growth were respectively five weeks, 



