312 PHYSIOLOGY [BoT. Absts., Vol. VII, 



has shown that the above reactions can be brought about by yeast juice and are due to a 

 special enzyme which has been named carboxylase, since it has the power of forming CO2 

 from the carboxylic group. This same enzyme has been found active in various organisms, 

 among which are various forms of Oidium and several bacterial species. The work of Neu- 

 berg and Reinfurth showed the role of sulphites in the production of acetaldehyde by the 

 yea^t cell, and the work of Neuberg and Kreb led to the assumption that methylglyoxal was 

 formed as one of the steps in the action, a substance which could easily yield glycerin. Thus 

 the classical formula of fermentation would take the form of C6H12O6 = CH3COH + CO2 + 

 C3H5(OH)3, and in presence of sulphites the action would be symbolized by C6H12O6 + 

 Na2S03 + H2O = C3H5(OH)3 + CH3CH(OH)O.S02Na + NaHC03. In 1919 Neuberg and 

 HiRSCH have shown that the living yeast if allowed to act in an alkaline medium in absence of 

 sulphites forms acetic acid in large quantities. A direct oxidation of the aldehyde can not be 

 assumed, since the action is taking place in an atmosphere of CO2; furthermore, the ratio of 

 acetic acid to glycerin is 1: 3. Applying the Cannizzaro reaction to the oxidation of acetal- 

 dehyde and uniting it with the reaction of Neuberg and Reinfurth we have: 2CH3COH + 

 H2O = CH3CH2OH + CH3COOH and 2C6H12O6 = 2C3H5(OH)3 + 2CO2 + 2CH3COH. A 

 list of the articles cited in the review is appended.—^. Bonazzi. 



2147. Fred, E. B., and W. H. Peterson. The fermentation of xylose by bacteria of the 

 aerogenes, paratyphoid B., and typhoid groups. Jour. Infect. Diseases 27:539-549. 1920. — 

 The medium used consisted of fresh yeast extract, containing 0.5 per cent dibasic potassium 

 phosphate, 0.5 per cent peptone and 2 per cent xylose. After the organisms were grown for 

 24 hours in the Smith fermentation tube, 2 cc. of sterilized mercury were added to check the 

 diffusion and escape of carbon dioxide. Xylose was found to be attacked by the organisms 

 of the aerogenes-typhoid group with the production of volatile, nonvolatile, and gaseous 

 substances, the by-products of the organisms included in this group differing quantitatively 

 and qualitatively. The products of fermentation with B. lactis aerogenes are essentially 

 carbon dioxide, hydrogen, and alcohol, and small amounts of a volatile acid. The products 

 of fermentation of B. paratyphoid B. are formic, acetic, butyric, lactic, and succinic acids, 

 ethyl alcohol, carbon dioxide, and hydrogen. The typhoid group does not attack xylose so 

 readily as the other organisms; the chief substances formed are formic, acetic, butyric, 

 and succinic acids, alcohol, and a trace of carbon dioxide. — Selman A. Waksman. 



2148. Klocker, Alb. Recherches sur las organisms de fermentation. IV Contribution k 

 la connaissance de la faculte assimilatrice de douze especes de levure vis-a-vis de quatre sucres. 

 [Researches on organisms of fermentation. Contribution to the knowledge of the assimilation 

 of four sugars by twelve species of yeasts.] Compt. Rend. Trav. Lab. Carlsberg 14^: 1-40. 

 1919. — Seven species of Saccharomyces, S. cerevisiae, S. Carlsbergensis, S. ellipsoideus , 

 S. Pastorianus, S. turhidans, S. Marxianus, S. fragilis, Zygosaccharomyces Priorianus, 

 Saccharomycodes Ludwigii, Debaryomyces globosus, Schwanniomyces occidentalis, and Schizo- 

 saccharomyces octosporus were tested for ability to assimilate dextrose, maltose, lactose, and 

 saccharose, using 3 different sources of nitrogen, viz., "yeast water," asparagin, and pep- 

 tone. The index of assimilation was cell multiplication; the number of cells in a culture was 

 determined at the time of sowing and after various periods of incubation by means of a 

 haematimeter. The sugars were added singly to yeast water or to a synthetic nutrient solu- 

 tion consisting of MgS04, KH2PO4, and either asparagin or peptone. Chemicals of highest 

 purity were used but the difficulty of avoiding introduction of minute traces of nitrogen in 

 the water, sugars, or salts used in the medium is pointed out. No statement as to the utili- 

 zation of a sugar by a given species is complete without specifying the source of nitrogen, 

 since both assimilation and cell multiplication vary with this. Yeast water was the most 

 favorable source of nitrogen, but peptone served as well in many cases, while asparagin was 

 either a favorable source or not utilized, depending on the species. A yeast may sometimes 

 assimilate a sugar which it is incapable of fermenting. No yeast organism has yet been 

 found capable of assimilating free atmospheric nitrogen. Dextrose and saccharose, in the 

 presence of yeast water, are utilized by all species studied; maltose is used by all but one, 

 Saccharomyces fragilis, which is unique in its ability to assimilate lactose. — F. Weiss. 



