1917] AGRICULTURAL CHEMISTRY AGROTECHNY. 509 



tive to the acidity and index of refraction of 15 samples of oil from different 

 Italian Provinces are submitted in tabular form. 



Tlie results show in general that whore the acidity is less than 2 per cent the 

 index of refraction is nearly always 63. With increasing acidity there is a 

 decrease in the index of refraction. The index of refraction was also found to 

 increase with the rancidity. 



The identification of emodin-bearing drugs, W. S. HunRARD {Jour. Indus, 

 and Enpin. Chcm., 9 (1017), No. 5, pp. 518-521). 



The biochemistry of tobacco. — I, Critical examination of methods for de- 

 termining' nitrogenous substances in tobacco leaves, G. Paris {Staz. Sper. 

 Agr. Ital., J,9 (1916), A'o. 7-8, pp. 405-Ji24) .—The author examined the various 

 methods for determining ammonia, amid, and nicotin nitrogen in tobacco, and 

 submits the methods which he has adopted for the continued study of the 

 subject. 



The drying of fruits and vegetables, Pearl MacDonald {Penn. State Col. 

 Ext. Circ. 61 (1917), pp. 12, figs. 10). — This circular gives brief directions for 

 drying cherries, cun-ants, hucklel)erries, apples, pears, quinces, peaches, shelled 

 peas and beans, green string beans, corn, and pumpkins, together with methods 

 of preparing dried fruits and vegetables. 



The influence of nitrogenous substances on the fermentation of fruit wines, 

 H. Mullee-Thurgau and A. Osterwalder (Landw. JaJirb. Schweis, 31 (1917), 

 No. 1, pp. 44-98. figs. 4)- — In the study reported it was found that, in cases 

 where the fruit juices were fermented only by the organisms that were present on 

 the fruit and without the addition of nitrogenous substances, there was great 

 variation in the fermentation, not only in the time of beginning, but also in 

 intensity. Even though the fermentation was slow where no pure yeast or 

 nitrogenous material was added, all the juices proceeded to complete fermen- 

 tation. Retardation of the fermentation in most of the juices is attributed to 

 the small amount of assimilable nitrogen present, as was indicated by the addi- 

 tion of various materials. 



The addition of ammonium chlorid stimulated the fermentation in juices to 

 which no pure yeast had been added. The stimulation varied in the different 

 juices, and also with the amount of ammonium chlorid added, and it was 

 evident only after the yeast cells had multiplied and required more nitrogen. 

 The addition of ammonia either exercised no influence or had an inhibitory 

 action on the fermentation. The influence of ammonium phosphate showed no 

 appreciable difference from that of ammonium chlorid. 



The use of pure yeast always stimulated the fermentation. The results 6f the 

 use of nitrogenous adjuvants with the pure yeast were similar to tho.se obtained 

 in the autofermentation experiments, the effect, however, being somewhat 

 greater. 



The addition of the nitrogenous substances to grape fermentations exercised 

 no stimulating action. A greater number of yeast cells and a marked improve- 

 ment in their general condition was observed in the cases where nitrogenous 

 substances were used. 



Chemical data relative to acid formation and other fermentation data are 

 submitted in tabular and graphical form and discussed. 



Chemical control in cane sugar factories, H. C. Prinsen Geeri.igs (London: 

 Norman Rodger, 1917, rev. and enl. ed., pp. XII+I40, fig. 1). — This volume con- 

 siders analytical methods, determination of quantities, stock taking, various 

 calculations, factory and laboratory instruments, tables, and models of books. 



[Keport of the] bacteriological department, W. L. Owen (Louisiana Stas. 

 Rpt. 1916, pp. 11-15). — Continuing work on the deterioration of sugars and the 

 principal factors affecting it (E. S. R., 35, p. 316), a number of samples were 



