1004 FOODS AND FOOD ADULTERANTS. 
ScHirr. Tannic acid, constitution and formula of. Ber. d. GAOT: Ges., 1872, 291, 438; 
Bull. soc. éhim. [2], 18, 23. 
ScuirF, H. Tannic acid, constitution of. Berichte, 1882, 258%; Jsb. d. Chem., 1882, 
915. 
ScumipT, E. Tannin. modification of Pribram’s method. Jsb.d. Chem., 1874, 1035; 
Bull. soe. chim. [2], 21, 256. 
HENHOUSE. Tannin, kinds of. Dingler’s polyt. Jour., 165, 150. 
SONNENSCHEIN. Tannin, action of, on Fehling’s solution. Analyst., 10, 205 
SIMAND, F. Gelatin, substitute for, in Léwenthal’s process. Analyst., 8, 125. 
TRIMBLE, HENRY. Tannins, the. J.B. Lippincott Company, Philadelphia. 
ULBRIcHT, R. Tannin, notes on Léwenthal’s method. Zeitsch. f. anal. Chem., 25, 
252; Ber. d. chem. Gesell. zu Berlin, 18, 1116. 
Voat, A. Tannin in the roots of plants. Wien. Acad. Ber., 53, 156; Jsb., d. chem. 
1866, 690. 
Watts. Tannin, criticisms on Fleck’s method. Jsb.d.Chem. 19, 887 (1868); Pharm. 
J. Trans. [2], 10, 223. 
CAFFETANNIC ACID. 
HLASIwetTz. Caffetannic acid, derivatives of. Ann. Chem. Pharm., 142, 219; Bull. 
soc. chim. [2], 9, 122; J. pr. Chem., 101, 97. 
KruG, W.H. The separation and ne of ae te acid. Original article 
in this report, page 908. 
LIEBICH. Caffetannic acid, action of KOH on. Jsb. d. Chem., 1849, 324; Ann. 
Chem. Pharm., Lxx1, 57; Pharm. Centralhalle, 1849, 855. 
BIBLIOGRAPHY OF METHODS FOR THE ESTIMATION OF CAFFEINE. 
ALLEN, A. H. A thin dough is made of the powdered tea, caustic lime, and water 
and the whole allowed to stand several hours. It is now dried on the water- 
bath, extracted with benzole, the benzole evaporated and the caffeine re- 
crystallized from water. Chem. News, 29, 129, 140, 167, 189, 221; 30, 2. 
BEEKMAN. The material is extracted with water containing a little sodium carbon- 
ate. The aqueous extract is mixed with an alum solution, the excess of 
alum precipitated by sodium carbonate and the precipitate filtered off. The 
filtrate and washings are evaporated to a syrupy consistence, made alkaline 
with sodium carbonate, and the caffeine extracted with ether. Zeitsch. f. 
anal. Chem., 4, 206. 
Brytu, A. W. This method is based on the ease with which caffeine sublimes. 
The author proceeds as follows: From one to two grams of finely powdered 
tea are boiled with water for an hour in a flask connected with an upright 
condenser. The whole is transferred to a porcelain dish, about its weight of 
magnesia added, and the mass evaporated nearly to dryness. It is now trans- 
ferred to an iron sublimmg plate and covered with a tarred glass funnel, the 
edge of which is accurately ground and which has a neck several inches 
long. The mixture is first heated to 110° C., then slowly raised to 200° C. and 
finally to 220° C. The caffeine sublimate is collected and weighed. Ana- 
lyst, 2, 39; also in Foods: Their Composition and Analysis, A. W. Blyth. 
CANADA, DOMINION OF. Ten grains of the finely ground sample are exhausted by 
repeated boiling with water, filtered, the filtrate made up to a definite vol 
ume, and an aliquot part precipitated with basic acetate of lead. The filtrate 
e without any concentration is shaken with successive portions of chloroform. 
The chloroform is removed by distillation and the caffeine is weighed. Re- 
port on Adulteration of Food, Supplement III, Report of the Dept. of Inland 
Revenue, 1886. 
CAZENEUYE-CAILLOL. Add to the tea four times its weight of boiling water and when 
the leaves become soft add an equal weight of slaked lime. Dry and extract 
