. Public health laboratory work, including methods employed in bacteriological research, with special reference to the examination of air, water and food contributed . per cent, in some samples. The other constituents of the tea leaf are : —cellulose,vegetable albumen, extractives (by alcohol), chlorophylland resin, pectin and pectic acid, dextrin or gum (Bell). An infusion of the leaves will be found to contain thedextrin or gum, tannin, thein, most of the salts, andsome of the albuminous substances, pectin, &c. A goodjudge of tea will form a ready and approximately accu-rate estimation of it
. Public health laboratory work, including methods employed in bacteriological research, with special reference to the examination of air, water and food contributed . per cent, in some samples. The other constituents of the tea leaf are : —cellulose,vegetable albumen, extractives (by alcohol), chlorophylland resin, pectin and pectic acid, dextrin or gum (Bell). An infusion of the leaves will be found to contain thedextrin or gum, tannin, thein, most of the salts, andsome of the albuminous substances, pectin, &c. A goodjudge of tea will form a ready and approximately accu-rate estimation of its purity and genuineness by thesmell and taste of a fresh infusion. The ash consists chiefly of potash—which amounts to CO 2 388 LABORATORY WORK. over 30 per cent, in most teas ; but also of phosphoricacid, carbonic acid, Hme, sulphuric acid, silica, alumina,iron, magnesia and soda. It does not appear, at first sight, an easy matter foradulteration to be practised in this connection, and yetformerly there were probably few articles of commerceless systematically exposed to fraud. Fortunately thisfraud —which is generally perpetrated before the leaves.
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Keywords: ., bookcentury1800, bookdecade1890, bookpublisherphiladelphiablakis
