1006 FOODS AND FOOD ADULTERANTS. 
he obtained 1.3 per cent caffeine from a tea known to contain 3.78 per cent. 
Boiling alcohol was then used and the rest of the caffeine was obtained. Ex- 
periments were made to determine whether caustic lime decomposed caf- 
feine. By experiment he determined that caustic lime does not decompose 
caffeine under the conditions obtaining in analysis, but that lime exerts a 
restraining influence on the extractive power with chloroform. Complete 
extraction of caffeine was obtained with boiling chloroform when magnesia 
was used. Pharm. J. Trans., March 1891, 882. 
Paut and COWNLEY. Five grams of powdered tea are moistened with hot water. 
well mixed with 1 gram of calcicum hydrate, and the whole dried on the 
water bath. The dry residue is then transferred to a small percolating appa- 
ratus and extracted with strong alcohol. The clear liquor is evaporated to 
remove the alcohol and the remaining water solution, which amounts to about 
50 ce, is mixed with dilute sulphuric acid which separates traces of lime and 
partially decolorizes the liquid. After filtering it is transferred to asepa- 
rator and well shaken with chloroform, about 200 cc, in five to six successive 
portions. The united chloroform solutions are then placed in a separator 
and shaken with very dilute sodium hydrate. This renders the caffeine quite 
colorless. The chloroform is then distilled off and the caffeine weighed. 
Phar. J. Trans., [3], 908, 417. 
PATROUILLARD, C. Fifteen grams tea are extracted with boiling water until com- 
pletely exhausted. The liquid is filtered, evaporated to the consistence of 
an extract, mixed with 2 grams calcined magnesia and 5 grams powdered 
glass,and dried. The residue is ground to powder, extracted three or four 
times with 60 cc of ether and this solvent then distilled off. The crystals 
of caffeine obtained are redissolved in chloroform and recrystallized. Chem. 
Ztg. No. 9, Feb. 26, 1880; Chem. News, 42, 259. 
Peticot. Make an aqueous extract of the tea, precipitate with lead acetate, add 
ammonium hydrate,andheat. Filter, pass hydrogen sulphide into the liquid, 
and filter again. Evaporate to a proper consistency and allow the caffeine 
to crystallize. This chemist determined the caffeine in exhausted tea leaves 
by means of a standard tannin solution, but does not give the details of his 
method. Zeitsch f. anal. Chem., 4, 207. 
Scuwakz, M. H. Exhaust the tea with boiling acidulated water, neutralize with 
lime, evaporate to dryness, and exhaust the residue with ether. Evaporate 
collect, and weigh the caffeine. Bull. Soc. Chim. de Paris Aug. 5, 1876, 3; 
Chem. News, 34, 94. 
SMITH, E. D. Coarsely powdered coffee (0.65 gram) is mixed with 0.13 gram mag- 
nesia, boiled 15 minutes with 150 ce water, filtered, and the filtrate made up 
to 300 ce by percolation. The filtrate is evaporated to 20 ce and the residue 
treated with 120 ce strong alcohol, transferred to a filter, and washed with 
alcohol. The alcohol is then drawn off and the residue dissolved by gradual 
addition of small quantities of water. This water solution is extracted three 
times With 25 ce chloroform. The chloroform is distilled off and the caffeine 
dried and weighed. Chem. Centrbl. 1887, 1270, 1271; Zeit. oesterreich. Apoth., 
Ver., 41, 359. 
SNYDER, Harry. Author states that the albuminoids of tea are almost entirely in- 
soluble in hot water. He extracts the powdered sample with four or five 
portions of hot water, collects the residue on a filter (S. & S. No. 589), and 
transfers filter and contents to a digestion flask, and determines the nitrogen 
by the Kjeldahl method. Total nitrogen in the sample (as determined by 
Kjeldahl method for alkaloids), less nitrogen of the insoluble portion, gives 
the alkaloidal nitrogen from which the caffeine may be determined. See 
Kozai’s article on teas, which gives the distribution of the nitrogen, page 
879, Journ. Anal. Chem., 4, 443. 
