here abuse is not followed by those terrible penalties which await the
drunkard or the opium-eater. Idiosyncrasy, too, may forbid their use;
and this is not very rare. As strengtheners and comforters of the
average human system, however, they have no superiors, and none others
are so largely used.

It is a little singular that the active principles of coffee and tea
are probably identical,--no more so, however, than the marvellous
similarity of starch, gum, and sugar, or other chemical wonders. They
have been called cafeine and theine, respectively. They are azotized,
and contain quite a marked amount of nitrogen. Chemically, they consist
of carbon 19, hydrogen 10, nitrogen 4, oxygen 4. Some allowance is
therefore to be made for them as plastic food.

This peculiar principle (theine) is also found in the leaves of the
_Ilex Paraguayensis_, or Paraguay tea, used in South America, as a
beverage.

"Good black tea contains of theine from 2.00 to 2.13 per cent.
Coffee-_leaves_ contain of theine from 1.15 to 1.25 per cent.
Paraguay tea contains of theine from 1.01 to 1.23 per cent.
The coffee-berry a mean of 1.00 per cent.

"Besides the theine and the essential oils, which latter give the aroma
of the plants, there is contained in both coffee and tea a certain
amount of difficultly soluble vegetable albumen, and in the latter,
especially, a large quantity of tannin. Roasting renders volatile the
essential oil of the coffee-berry. The tea-leaf, infused for a short
time, parts with its essential oil, and a small portion of alkaloid,
(theine,) a good deal of which is thrown away with the grounds. If it