614 EXPERIMENT STATION RECORD. [Vol.41 



Waxes, by C. Revls and E. R. Bolton; Paints, Pigments, Varnishes, and 

 Resins, by L. M. Nash; India Rubber, by D. F. Twiss; Leather and Glue, by 

 F. C. Thompson; Agricultural Chemistry, by E. J. Russell; Sugars, Starches, 

 and Gums, by J. P. Ogilvie; Foods, by H. W. Bywaters; Water Purifieation 

 and Sanitation, by E. Ardern ; Fine Chemicals, Medicinal Substances, Essential 

 Oils, by G. Barger ; and Photographic IMaterials and Processes, by B. V. Storr. 



In the sections on Agricultural Chemistry and Foods the literature of the 

 past three or four yeaers is reviewed, while the remaining sections cover, in 

 general, the literature of 1918. In all sections the influence of war conditions 

 on the trend of progress in applied chemistry is shown. 



Acid fermentation of xylose, E. B. Fred, W. H. Peterson, and A. Davenport 

 (Jour. Biol. Chem.. 39 {1919), No. 2, pp. 847-383, pi. 1, figs. 3).— Organisms have 

 been isolated from sauerkraut, silage, and manure which are capable of fer- 

 menting xylose rapidly, with the formation of acetic acid and lactic acid in 

 the proportion of about 43 gm. of the former to 57 gm. of the latter, the two 

 acids together representing about 90 per cent of the sugar consumed. The 

 maximum amount of acid per gram of xylose fermented is obtained in cultures 

 containing from 2 to 3 per cent of xylose. Sugars other than xylose are fer- 

 mented by these organisms with the production of acetic and lactic acids, but 

 in much smaller amounts. 



The organisms, to which the name Lactobacillus pentoaceticus n. sp. has 

 been given, are nonsporing, gram-positive, facultative anaerobes growing best 

 with a lowered oxygen tension and at a pH of from 3 to 8.6. In yeast water 

 or cabbage juice solutions xylose is fermented much more rapidly than in 

 water solutions containing nitrogen from beef extract, peptone, or gelatin. 



The authors call attention to the occurrence of these organisms in silage and 

 their possible significance in the production of the acids of silage. 



The action of ptyalin, H. McGuigan (Jour. Biol. Chem., 39 {1919), No. 2, pp. 

 273-28Jt). — The action of ptyalin upon starch was determined by digesting a 

 starch solution in an incubator at 40' C. with varying amounts of saliva, 

 diluted 1:5 or 1 : 10, and filtered. One or 2 cc. samples of the digest were 

 taken at stated Intervals, boiled with 8 cc. of Benedict's picric acid solution 

 and 2 cc. of 20 per cent sodium carbonate, made to a convenient volume, and 

 matched in the calorimeter against a standard containing 1 or 2 cc. of a 0.1 

 per cent dextrose solution. 



The results obtained, which are considered to be accurate within 5 per cent, 

 indicate that ptyalin in dilute solutions acts on starch at a rate directly pro- 

 portional to the amount of ptyalin present until digestion is interfered with 

 by the products formed. The point of equilibrium is reached when about 70 

 per cent of the starch calculated as dextrose is converted into sugar. The 

 chief cause of the establishment of equilibrium has not been discovered, but 

 the theory is advanced that, since practically the same amount of sugar is 

 formed by the same amount of ptyalin in varying concentrations of starch 

 solutions, the ptyalin may unite quantitatively with the starch during digestion 

 and exert a force which causes hydrolysis. When the starch molecule is con- 

 verted into sugar the ptyalin is again free to unite with more starch. Dextrose 

 and maltose are thought not to interfere with the normal process of digestion 

 of the starch. 



Note on the preparation of a purified ag'ar powder with increased powers 

 of filtration, J. Cunningham {Indian Jour. Med. Research, 6 {1919), No. 4, pp. 

 560-568, figs. 2). — The method described consists of a preliminary soaking of the 

 crude agar for ten minutes with dilute hydrochloric or sulphuric acid, after 

 which the product is thoroughly washed with running water until all traces of 



