ADULTERATION AND DETECTION. 153 



two-thirds of distilled water accurately measured, a cork 

 and bent tube is then adapted to the mouth of the flask 

 and a connection made with a condenser. The contents 

 of the flask are next heated and made to boil strongly. 

 That having been done the boiling is stopped and the 

 flask and condenser disconnected and the distillate 

 poured back into the flask and the decoction of tea 

 observed closely. If quite clear fifty grams are weighed 

 out and evaporated to dryness in a water-bath and 

 weighed till constant. If the decoction be not quite 

 clear by this time it is to be filtered hot ; the first small 

 filtrate is best thrown away and the filtrate collected, 

 weighed, and dried in the water-bath until the residual 

 tea-extract becomes quite constant. Having performed 

 the operation in the manner directed, the weight of the 

 tea-extract actually weighed will be the weight of the 

 extract yielded by one gram of the sample to be assayed. 

 But in coming to a decision as to the genuineness of 

 a sample of tea of which an analysis has been made by 

 this method, it is of importance to remember that genuine 

 tea is subject to considerable variation in composition. 

 The quality and condition of the leaf at the time of 

 gathering and the different treatments which it under- 

 goes in the process of manufacture, or whether the tea 

 is Black or Green, cause the composition to exhibit a 

 wide range of variation. Taking the percentage of the 

 extract as a basis from which to start, that in genuine tea 

 being from 32 up to 50 per cent, in its ordinary com- 

 mercial condition. Such being the case, it is obvious 

 that a determination of the percentage of extract will 

 not enable the expert or analyst to say whether the 

 sample of tea be of a lower or higher grade of pure tea, 

 or whether it is composed of a high grade of genuine tea 

 and a portion of exhausted leaves. In a general way, 



