430 Dr. Stenhouse on Theine and its Preparation. 



spirits of wine, but it is not soluble in aether. Its colour is 

 immediately destroyed by a solution of potash, which does 

 not change it to an indigo-blue, as it does murexide. The 

 substance which gives the red colour with ammonia does not 

 appear to be crystal lizable. 



Now as I obtained the purple colour as readily from theine 

 prepared from Paraguay tea as from that made from ordinary 

 tea and coffee, I have not the least doubt that they are both 

 identical substances. Unfortunately, from the smallness of 

 the quantity of Paraguay tea in my possession, I have not 

 been able to procure more than a few grains of the theine in 

 a state of purity, and have been prevented therefore for the 

 present from subjecting it to analysis. This however I have 

 good reason to believe I shall be able to do in the course of 

 a few weeks. 



The quantity of theine in Paraguay tea is by no means 

 great, but no doubt much of what it originally contained had 

 been destroyed by the injudicious way in which it is manufac- 

 tured in Paraguay. The branches of the yerba tree are 

 there cut down and spread upon a sort of wooden barbacue, 

 under which large fires are kept burning. The yerba is 

 therefore exposed to a very high temperature, and as theine 

 sublimes pretty readily, it is plain that a good deal of it will 

 necessarily be dissipated. 



It is somewhat singular, as Professor Liebig has observed, 

 that the other three vegetable substances which are known to 

 contain theine, tea, coffee, and guarana, though derived from 

 plants of very different natural families, are all of them exten- 

 sively employed as refreshing beverages. The circumstance 

 that Paraguay tea, which is extensively applied to precisely 

 the same purpose, also contains theine, is calculated, I should 

 think, to give additional probability to the views of Professor 

 Liebig on this subject. 



It is not unlikely that theine will soon be found to occur in 

 other vegetables besides those in which it is already known. 

 The easiest way perhaps to examine a plant for theine, which 

 can be done in the course of a few hours, is to precipitate its 

 infusion with subacetate of lead, to filter and evaporate the 

 clear liquid to dryness. If a portion of the matter thus ob- 

 tained be distilled, any theine it may contain will be imme- 

 diately deposited in long flat crystals on the neck and sides of 

 the retort. 



Camellia Japonica. — Through the kindness of Professor 

 Balfour I was enabled to examine a quantity of the leaves of 

 the Camellia Japonica, a plant whose botanical characters 

 approach very closely those of Tea Bohea. I found that the 



