It evidently decomposes during fermentation. The amount of theine is practically the same in both. In the finest teas, the proportion of theine is large. Of great practical value and, of course, much simpler than the chemical analysis, is the infusion test, as carried out by experienced tea brokers. This procedure removes only 20 per cent of extractive matter, while, if the tea were completely exhausted, about 35 to 40 per cent would be yielded, including all the tannin, which would make the decoction unpalatable and harmful.
Tea is much subject to adulteration.
The improvement of the flavor has been mentioned. Catechu has been added to increase the astringency. Action, Medical Uses, and Dosage. Used in moderation, the infusion, when not too strong, is a harmless and refreshing beverage. As to its effects upon the constitution, there is quite a diversity of opinion, but it is very probable that, with healthy persons, no pernicious influences arise from its use, unless taken in large quantities, or very strong.