604 EXPERIMENT STATION RECORD. 



sometimes yields results which vary from the correct figure not less than from 

 0.4 to 0.5 per cent. This is due to the fact that potassium bitartrate is not 

 altogether insoluble in alcohol, and also to the action of the neutral potassium 

 tartrate on freshly precipitated calcium carbonate. 



The author points out that the error due to the first cause may be eliminated 

 by treating the potassium bitartrate with standard caustic alkali, just as though 

 it were a sample of argol, instead of titrating it directly. He also points out 

 that where a high lime content is present the amount of potassium carbonate 

 specified by Goldenberg is insuflicient, and is liable to indicate very much less 

 tartaric acid than is present in the sample. Other errors may be introduced 

 by mechanical losses during evaporation. 



Estimation of total tartaric acid, A. Heczko {Ztschr. Analyt. Chenu, 50 

 {1911), No. 2, pp. 73-82; abs. in Analyst, 36 {1911), No. J,21, pp. l.',8, lJi9).~ 

 An investigation of the Moszczenski method ** showed that with pure tartrates 

 the results are correct, but with crude tartar they are from* 1 to 2 per cent too 

 high. The method is, however, more rapid than the Goldenberg process. 



Methods for estimating- ethyl alcohol quantitatively, A. Baudrexel {Deut. 

 Essigindus., 15 {1911), No. 9, pp. 67-69). — A discussion in regard to the existing 

 methods for the quantitative determination of alcohol. 



Hydrolysis of casein, T. B. Osbokne and H. H. Guest {Jour. Biol. Chem., 9 

 {1911), No. 3-.'i, pp. 333-353). — On the basis of a summary of data, including 

 the investigations reported and earlier work from Osborne's laboratory, it is 

 l)oiuted out that there is a relatively large discrepancy between the sum of the 

 nitrogen of known decomposition products of casein and the total theoretical 

 amount. Possible explanations are suggested. 



The paper as a whole is an important contribution to the chemistry of casein. 



The occurrence of sucrose in grapes, W. B. Alwood {Jour. Indus, and Engin. 

 Chem., 2 {1910), No. 11, pp. -'{81, Ji82). — The author and his coworkers "found 

 sucrose in several varieties of grapes belonging to the species commonly cul- 

 tivated in the United States, but more especially in a new seedling grape dis- 

 covered growing near Sandusky, Ohio, which was until then unknown to horti- 

 cultural literature. 



" The known varieties in which sucrose was found to occur are Hayes, 

 Pocklington, and Worden. These showed sucrose in quantities varying from 

 4.49 to 5.66 gm. per 100 cc. of juice. The new seedling, however, showed sucrose 

 varying at different dates from 7.06 to 9.73 gm. per 100 cc. of juice, with a total 

 sugar content varying from 15.93 to 19.52 gm. per 100 cc. of juice. . . . [The 

 author and his coworkers] have now examined in the laboratory a large series 

 of samples of practically all the wine and table grapes grown in the Eastern 

 States, and in no case other than mentioned above have [they] found sucrose 

 in appreciable quantity." 



The occurrence of sucrose (cane sug-ar) in unfermented grape juice {Pure 

 Products, 7 (1911), No. S, pp. 434, 7/35).— Substantially noted above. 



Enological studies, W. B. Alwood ( U. S. Dept. Agr., Bur. Chem. Bui. I40, 

 pp. 2-i). — In -addition to reporting what is noted in the abstract above, the 

 author in this bulletin gives the results of examining the Illinois City, Nectar, 

 Norton, Catawba, and Montefiore varieties of grapes for sucrose. Sucrose was 

 present in appreciable quantities in the first three varieties and in the last 

 two, in amounts ranging from 0.04 to 0.4 per cent, which, according to the 

 author, does not point positively toward the presence of sucrose. 



Comparing the results obtained by examining the seedling grape (see abstract 

 above) from the time it became edible until it was overripe during 1909 with 



«Jour. Soe. Chem. Indus., 17 (1898), p. 215. 



