104 University of Calif vrnia Publications in Agricultural Sciences [Vol.3 



increase in sugar content and changes in acidity during the period 

 in which the grapes were under observation. Alwood and other mem- 

 bers of the Bureau of Chemistry, United States Department of Agri- 

 culture, have also published a number of reports 4 on the general 

 composition of American varieties of grapes as affected by season, 

 locality, etc. 



The most notable changes taking place during ripening were found 

 by the European and American investigators mentioned above to be : 

 (1) increase in total sugar ; (2) decrease in ratio of glucose to fructose ; 

 (3) decrease in total acid; (4) increase in ratio of cream of tartar to 

 total acid due to decrease in total acid ; (5) decrease in tannin ; and (6) 

 increase in coloring matter. The cream of tartar and protein change 

 very little in percentage during ripening, although, according to the 



composition of varieties of grapes m Abraon-Durso. Ann. Soe. Agr Sci. et Intl., 

 Lyon (8), vol. 1 (1903), pp. 97-159. 



Laborde, J., The transformation of the coloring matter of grapes during 

 ripening. C. E, Aead. Sci. (1908), vol. 17, pp. 753-755. 



Martinand, V., On the occurrence of sucrose and saccharose in different parts 

 of the grape. C. E. Acad. Sci. (1907), vol. 24, pp. 1376-79. 



Boos, L., and Hughes, E., The sugar of the grape during ripening. Ann. 

 Falsif. (1910), vol. Ill, p. 395. 



Bouffard, A., Observations in regard to the proportion of sugar during ripen- 

 ing. Ann. Falsif. (1910), vol. Ill, pp. 394-5. 



Zeissig, Investigations on the process of ripening on one-vear-old grape wood. 

 Ber. k. Lehranst. Wien, Obst-u. Garten-bau (1902), pp. 59-64. 



Koressi, F., Biological investigations of the ripening of the wood of the 

 grape. Eev. Gen. Bot., vol. 13 (1901), no. 149, pp. 193-211; no. 150, pp. 251-264; 

 no. 151, pp. 307-325. 



Brunet, E., Analvsis and composition of the grape during ripening. Eev. 

 de Viticulture, vol. 37, pp. 15-20. 



Garina, C., Variations in the principal acids of grape juice during the process 

 of maturing. Canina. Ann. E. acad. d 'agricultura di Torino, vol. 57 (1914), 

 p. 233. Cf. Ann. Chim. applicata, vol. 5 (1914), pp. 65-6. See also Ann. r. acad. 

 d 'agr. di Torino, vol. 57, pp. 233-90. 



Baragolia, W. I., and Godet, C, Analytical chemical investigations on the 

 ripening of grayjes and the formation of wine from them. Landw. Jahrb., vol. 

 47 (1914), pp. 249-302. 



Biviere, G., and Bailhache, G., Accumulation of sugar and decrease of acid 

 in grapes. Chem. Abs. Jour. (1912), p. 1022; Jour. Soc. Nat. Hort. France (4), 

 pp. 125-7; Bot. Cent., 1912, pp. 117, 431. 



Pantanelli, Enzvme in must of overripe grapes. Chem. Abs. Jour., vol. VI 

 (1912), p. 2447. 



* Alwood, W. B., Hartmann, J. B., Eoff, J. E., and Sherwood, S. F., Develop- 

 ment of sugar and acid in grapes during ripening. U. S. Dept. Agric. Bull. 335, 

 April 11, 1916. 



The occurrence of sucrose in grapes. Jour. Indust., vol. II, Eng. Chem. 



(1910), pp. 481-82. 



Sugar and acid content of American native grapes. 8th Inter. Cong. 



Appl. Chem. (1912), Sect. Vla-XIv, pp. 33, 34. 



Enological Studies: the chemical composition of American grapes grown 



in Ohio, New York, and Virginia. U. S. Dept. Agric. Bur. Chem. Bull. 145, 1911. 



Crystallization of cream of tartar in the fruit of grapes. U. S. Dept. 



Agric. Jour. Agric. Eesearch (1914), pp. 513, 514. 



Ahvood, W. B., Hartmann, B. G., Eoff, J. E., Sherwood, S. F., Carrero. J. O., 

 and Harding, T. J., The chemical composition of American grapes grown in the 

 central and eastern states. U . S. Dept. Agric. ( 1916) Bull. 452. 



