^^^ OF ECOlSrOMIC PLANTS. 405 



and ultimately in 1865 to 6d. per pound, pnt an end to the 

 manufacture of home-made tea. Before the political and trade 

 arrangements with China, Canton was the only port open to 

 trade with foreigners, and all teas were examined before ship- 

 ment by a special officer appointed by the East India Company, 

 called the Tea-taster; this had the effect of insuring genuine 

 tea ; but since the opening of other ports and the demand for 

 tea continuing to increase, and the office of tea-taster being 

 abolished, the opportunity of again adulterating tea has presented 

 itself, and is carried on to a great extent a£ the present time. 

 About thirty years ago tea began to be cultivated in Assam, 

 and being successful has led to the formation of companies for 

 cultivating it in various parts of India suitable to its growth, as 

 also in Ceylon, where it has been eminently successful; no less 

 than 45,371,704 lbs. were exported from India to this country 

 in 1880. Tea having become a universal beverage in all civil- 

 ised countries has led Japan to compete with China, and to 

 furnish the United States with their principal supply. Russia 

 and other nations of Northern Asia receive their tea from China 

 made up into solid, hard lumps called Brick Tea, which is boiled 

 and eaten like a vegetable. It was long supposed that black 

 and green teas were the produce of distinct plants, the former 

 from Thea hohea, and the latter T. viridis; but it is now known 

 that both kinds are made indiscriminately from the same plant, 

 the difference depending on the age of the leaf when gathered, 

 and the mode of preparing. Originally pure green tea was 

 considered the finest, and fetched the highest price ; the demand 

 led black tea to be artificially coloured, even almost to shiny 

 blue, as was at one time to be seen in grocers* windows, the 

 substances used being indigo, turmeric, prussian blue, and 

 gypsum, specimens of which are to be seen in the Museum at 

 Kew, and were obtained by'^Dr. Seeman on visiting a tea 

 manufactory at Canton. The active principle of tea is called 

 Theine ; different opinions are entertained of its effects on the 

 human frame when used as a daily beverage, but it may be 

 considered beneficial, as the same principle, theiney is found in 



