206 CHEMICAL, MEDICAL AND DIETICAL PROPERTIES. 



submitted, the results have been as varied. The average 

 composition in parts range as follows : 



Chemical Constituents. Quantities. 



Theine, 3 



Tannin, 25 



Volatile Oil, I 



Albuminoids, 15 



Mineral Matter, 6 



Gum and Glucose, 21 



Vegetable Fibre, 20 



Fatty Substances 4 



Water of Absorption, 5 



Total, 100 



Theine Is the alkaloid of tea and is the substance 

 to which it owes its refreshing and stimulating properties. 

 It is a crystallizable matter, soluble in water, very 

 bitter to the taste and characteristic alike of both tea and 

 coffee, being to these beverages what quinine is to bark, 

 and with the base of cocoa which has recently received 

 the name of " theobromine," it is also closely related. It 

 is further remarkable as occurring in many other plants 

 dissimilar in structure and character, grown in remote 

 countries, but yet selected by the inhabitants on account 

 of their yielding a slightly exciting and refreshing bever - 

 age, and to the presence of which the peculiar physio- 

 logical action of tea on the animal economy is attributed. 

 It was first discovered under the name of Caffeine by 

 Runge, who originally found it in Coffee, and later by 

 Oudry, who extracted an identical substance from tea, to 

 which he gave the name of Theine. Strickler subse- 

 quently produced it from cocoa, naming it Theobromine. 

 These bodies are evidently related to uric acid as like it, 

 when exposed to the action of nitric acid and ammonia 

 they yield a purple coloring matter, technically termed 

 murioxide. 



