506 EXPEEIMENT STATIOK RECORD. 



of emulsin, and they were kept at room temperature for from 16 to 21 days 

 amid occasional shaking. After this period both mixtures were found to .have 

 exactly the same rotation. If the strength of the alcohol was varied, the actual 

 final rotation was found to vary accordingly, the greater the alcohol dilution, 

 the greater being the hydrolysis. 



The results obtained are regarded as confirming the true reversibility of 

 enzym action. 



The supposed reversibility of the hydrolysis of salicin by enzyms, G. 

 Bertrand and A. Compton (Compt. Rend. Acad. 8ci. [ Pari^], 154 {1912), No. 

 24, pp. 1646-1648; al)S. in Jour. Chem. 8oc. [London^, 102 (1912), No. 597, I, pp. 

 592, 593). — The proofs given for the reversible nature of emulsin for salicin are 

 not regarded as adequate. In a series of experiments carefully controlled, in 

 which the reducing effect of the dextrose formed was noted, it was found that 

 salicin in 1 and 3 per cent solutions at various temperatures is completely 

 hydrolyzed in a comparatively short time. Even when a little salicin is intro- 

 duced into equimolecular quantities of the products of hydrolysis (dextrose and 

 saligenin), the addition of emulsin caused hydrolysis of the salicin. 



Analytical chemistry, F. P. Tkeadwell, trans, by W. T. Hall {New YorTc 

 and London, vol. 1, 1913, 3. ed., rev. and enl., pp. XIII+534, pl. 1, figs. 25; vol. 2, 

 1911, pp. XI +903, pl. 1, figs. 129). — These editions have been compared with the 

 fifth German edition, and deal with qualitative and quantitative analysis. "A 

 new chart of the more important spectra is given [in the first volume], and the 

 wave lengths of the different rays of light stated. Oxidation and reduction 

 equations are explained more on the basis of the electron conception of valence 

 than in accordance with the old dualistic theory, and in this, as well as in other 

 points, the translation does not follow the German text." 



The examination of waters and water supplies, J. C. Theesh {Philadelphia, 

 1913, 2. ed., pp. XX+644, pis. 37, figs. 16). — In this second edition (E. S. R., 16, 

 p. 844) the various sections of the book have been amplified, one or two have been 

 entirely rewritten, and two others added, as well as a few more plates on 

 deposits found in water. Bacteriological standards are discussed at length in 

 chapter 10. 



rood analysis, H. Bauer {Nahrungsmittelchemisches PrakUkum. Stuttgart, 

 1911, pp. VIII+252, figs. 36).— This is an introduction to the physical and 

 chemical methods used in the examination of foods and condiments, these being 

 concisely described. 



Yearly report in regard to the progress made in the examination of foods 

 and condiments for 1911, H. Beckurts, H. Frerichs, and H. Emde {Jahresier. 

 Untersuch. Nahr. u. Genussmtl., 21 {1911), pp. 195). — This continues previous 

 reports (E. S. R., 27. p. 310). 



An improved method of crude fiber estimation, E. B. Forbes and J. E. Men- 

 SCHING {Jour. Indus, and Engin. Chem., 5 {1913), No. 3, p. 258).— This is an 

 improvement of the M. P. Sweeney modification of the official method (E. S. 

 R., 28, p. 206), as follows: 



" To a 1- or 2-gm. sample, add 200 cc. of boiling 1.25 per cent sulphuric acid, 

 and boil for 30 minutes. Neutralize with 10 per cent sodium hydrate, using 

 phenolphthalein as an indicator; add 200 cc. of 2.656 per cent boiling sodium 

 hydrate ; make volume up to 425 cc. and boil for 30 minutes. Filter through a 

 porcelain Gooch crucible containing an asbestos pad and 10 to 12 gm. {i in.) of 

 very fine acid-washed sand, compacted by water and suction. Treat with 

 hydrochloric acid; wash with hot water until free from chlorids, and then with 

 alcohol and ether; dry, weigh, ignite, and weigh. . . . Coarse sand was found 

 not to be useful, the reason being that it allows the fiber to pass through and 

 then to clog the asbestos pad. 



