12 



tical with caffeine, both having the same analytical formula, 

 C 1 II'" N 1 O 8 and H < >. The formula for the active principle 

 of chocolate shows it to be simpler in constitution; this is 

 named theobromine, having the composition ( ' II s N 1 <) : 

 To those who have some knowledge of organic chemistry the 

 close relationship of caffeine to theobromine will be obvious, 

 1'ur if one atom of hydrogen in theobromine be substituted 

 by the compound radical methyl, the formula for which is 

 CH 8 * caffeine is formed theoretically as a substitution com 

 pound, and hence the chemical name for caffeine becomes 

 " niethyl-theobromine." Caffeine is contained in the follow- 

 ing proportions in the beverage substances named: in tea, 

 about 2 per cent.; in coffee, 0.8 to 1.3 per cent.; in prepared 

 guarana, 5 per cent.; in Paraguay tea, about 1.2 percent ; 

 and in kola-nut, 2J> per cent., which last will be noticed as a 

 very high percentage. 



The alkaloids from all these sources have two properties 

 in common; they are stimulant and anti-metabolic; and thus 

 it is that the substances which contain them, when blended 

 with nutritious natter, are suitable for use as beverages in 

 the dietary. The term " anti-metabolic" will require explana- 

 tion. It is a word used to express the arrest of tissue-change 

 in muscle and brain, and neve and other tissues, which or- 

 dinarily goes on in our bodies in the course of our daily ex- 

 ercise. An anti-metabolic substance, then, is one which 

 checks exhaustion. 



Tea furnishes a good example of this combined action 

 of stimulation with a check to the processes of wear and tear. 

 The stimulant and cheering qualities of tea are too well 

 known to require dwelling upon; its nutrient qualities, how- 

 ever, are slight, but it will be interesting to know that, the 

 younger the leaf is picked, the more stimulant and nutritious 

 it is. This is a matter of quite recent discovery; and as tea 

 as an article of cultivation has its claims for attention in 

 Jamaica, where we have land and climate extending from tin; 

 plains to the JJIue Mountains in every way suitable to it; 

 and as tea cultivation in this Island is one of the possibilities 

 of the near future, I present the fact to the public that in 

 due time it may bear fruit. It has been ascertained that the 

 young leaves of tea contain more of the active principle, 

 theme, than old leaves, that the chief nutritious element is a 

 mineral substance, phosphate of potassium, which is soluble 

 in tea infusion, and which of itself possesses restorative 

 qualities ; whilst as the leaves get older they contain more 

 woody fibre and astringent matter, and the soluble phosphate 

 of potassium undergoes a chemical change into phosphates of 

 lime and magnesia, which are insoluble and inert. There 

 can be no good tea unless it consists of the young leaf; and 



