208 CHEMICAL, MEDICAL AND DIETICAL PROPERTIES. 



happens that the theine makes its appearance in the 

 infusion instead of remaining in the exhausted leaves. 

 The proportion of theine in tea has been variously 

 given by different chemists. Mulder finding 0.43 per 

 cent, in Green tea and 0.46 in Black, while Stenhouse 

 found 1.05 and 1.27 in Green and Black respectively. 

 Peligot found 2.34 and 3.0, and Zoller, whose research is 

 comparatively recent, found 3.94 per cent, of theine in 

 India tea. But it would be a mistake to regard these 

 varying results as showing that the quantity of theine 

 in tea is variable, as they serve only to illustrate the diffi- 

 culties which stand in the way of a quantitive extraction 

 of the theine, and the imperfection of the earlier methods. 

 In Peligot's paper, these difficulties are referred to, and by 

 making an attempt to extract the theine from a sample 

 of tea the chemist acquires a sense of the truth of them. 

 The experiments of the latter, however, being of great 

 interest to chemists merits a somewhat detailed descrip- 

 tion. He began by determining the total amount of 

 nitrogen contained in the dried leaves of different kinds 

 of China tea at 110, finding 6.15 per cent, in 100 parts 

 of Oolong, 6.58 in Congou, and 6.30 in Green tea, while' 

 from one sample of India he extracted only 5.10 per cent, 

 proportions six times greater than had been heretofore 

 obtained by any previous analysis. Next testing every 

 soluble substance for nitrogenous matter, he proceeded 

 by successive eliminations to ascertain the quantity of 

 theine in 27 other different samples and found that Green 

 teas contained on an average 10 per cent, of water, and 

 Black only 8 per cent., and also that the latter contained 

 about 43.2 of matter soluble in boiling water while the 

 former averaged as high as 47.1, and that this soluble 

 matter yielded only 4.35 of nitrogen in Black teas, and 

 ^70 per cent, in Green. It remaining to be determined 



