86 CAFFEIN-YIELDING PLANTS. 



brown ; limewater gives a white precipitate, turning blue ; ferro- 

 cyanide of potassium in ammonia, Indian red. The tea tannin 

 coagulates albumen of the egg and gelatine, and gives precipi- 

 tates with alkaloids and with tartar emetic on addition of sal 

 ammoniac. 



There are many adulterations made in Europe by mixing 

 the genuine tea with leaves of other plants. The Sloe (Pr'unm 

 spinosa, L.) takes the first place. There is much tannic acid 

 contained in the sloe leaves, but they are easily recognised, 

 being much thinner than tea-leaves, and the same holds good 

 for adulterations with the leaves of strawberries, roses, and 

 blackberries. Besides this, the leaves of the sloe give a green 

 reaction with ferric salts, and a golden yellow 'one with caustic 

 potash. 



The tea prepared from unfermented tea-leaves possesses 

 just the same good qualities as that from fermented leaves, but 

 it is nearly destitute of flavour. On a farm with deep soil and 

 a good drainage, enough tea shrubs could be kept in any part of 

 Queensland to supply the whole family with tea for a year, and, 

 as the fermentation could be dispensed with, it would not give 

 any trouble. 



The Paraguay Tea, or Mate {Ilex parar/uayensis), is a near 

 relation to the European Christmas Holly. It is a small ever- 

 green tree with shiny glabrous crenate oval leaves. It grows all 

 over South America, and its leaves, mostly gathered from the 

 wild plant, are just dried and roasted a little, without having 

 undergone any fermentation, and after having been reduced to 

 powder, are used like Chinese tea. As they contain less caffein 

 a larger quantity of them is wanted for a good cup of tea. The 

 Mate Tree grows remarkably well in the Brisbane Gardens. For 

 my investigations I got a good supply through the kindness of 

 the Curator, Mr. MacMahon. The fresh leaves contain 63 per 

 cent, of water, 5-5 per cent, of tannic acid, and 0*4 per cent, of 

 caffein, besides 30 per cent, of other substances. From the dry 

 leaves I obtained 1-1 per cent, of caffein, so that nearly half an 

 ounce of Paraguay tea is wanted to make a good cup of tea, 

 equal to one prepared from one drachm of good China tea. 



In Clamor Marquart's "Pharmaceutical Chemistry," the 

 tannin of Paraguay tea is stated erroneously to be identical with 



