Page:Food and cookery for the sick and convalescent.djvu/97

Rh diet. Clam water and oyster liquor sometimes stimulate the appetite. Clam water, administered in small quantities, is especially valuable in relieving extreme cases of nausea; in larger quantities it acts as a laxative.

Egg-nogs, and other beverages in which eggs are used, play a most important part in the dietary of the sick, for by their use nutriment in a concentrated form is easily administered.

The leaves of the evergreen shrub, Thea, furnish the tea of commerce, both black and green.

The best brands of black tea are imported from India and Ceylon; the best green tea comes from Japan, and a small quantity from China. Tea leaves before curing have neither odor nor flavor.

There are four gatherings annually. The first picking comes in April, and is considered the best.

Climate, elevation, soil, cultivation, selection of the leaves, and the care in the picking and curing of them, all go to make up the difference in quality. First quality tea is made from the young, tender, whole leaves. In black tea the leaves are allowed to ferment, while in green tea the leaves are unfermented.

Tea is a stimulant rather than a nutrient. Its stimulating effect is due to the alkaloid thein and a volatile oil. Its astringency is due to tannin. Black tea contains less tannin than green tea, while the thein and oil vary but little.

Tea should always be made as an infusion, by the use of freshly boiled water, with but one infusion to each measure of tea. The practice of allowing tea to boil, or allowing leaves to be used and reused with a small additional supply, cannot be too strongly condemned. The thein is so soluble that it is almost immediately dissolved out of the leaf. Tannic acid is developed as soon as tea is placed in boiling water, but in a small quantity. Experiments have shown that more tannic acid is developed in a five-minute than in a three-minute