Infusion

The flavour of tea depends not only on the character of the leaves, but upon that of the water which is added to them. About five grammes of leaves should be used for one infusion. The water should be poured upon the tea leaves when boiling, and the infusion should not last beyond three or four minutes if the flavour is to be delicate; if it is continued beyond this point materials become extracted from the leaves which, while they may make the tea appear stronger, materially diminish the delicacy of its flavour. The water should be neither too hard nor too soft. Soft water extracts more of the soluble materials of the leaves and yields a beverage of darker colour. Water which contains iron or lime salts should be boiled with sodium carbonate before it is used for tea infusion.

Physiological And Therapeutic Action

Good Effects

Tea is mildly stimulating to the nervous system and tends to increase the activity of certain vital functions. It is refreshing and relieves bodily fatigue. For the latter purpose it has been found especially useful for soldiers on the march in hot climates. 16

Major Woodruff, U. S. A., says: "The universal experience of military men testifies to the absolute necessity of tea or coffee. The latter is generally preferred, but the writer's experience points to tea as preferable in the long run." For this purpose both these substances are better preserved if compressed into small bulk.

In some persons a cup of hot tea affords prompt and decided relief from headache, and when taken quite strong it is sometimes serviceable in the cure of chronic alcoholism. It is also used as an antidote for opium poisoning, but coffee is preferable.

The "strength" of tea as applied to the appreciation of its taste in distinction from its effect on the nerves is due to the quantity of tannin present, which is bitter. A bitter tea is not therefore necessarily a strong one in its stimulating properties, which are owing to the theine.

Tea, when employed as a beverage, possesses some effects which are not strictly due to action upon the nerves. It introduces considerable hot water into the system, which is beneficial when taken at the proper time in relation to meals, and when milk or cream and sugar are added its nutritive value becomes considerable. Tea is moderately sudorific in action, and it has a slight influence in regulating the circulation and temperature of the body, which, if too cold, becomes warm by the stimulating effect upon the heart, whereas if the body is too hot, tea may exert a cooling influence by increasing perspiration and evaporation from the surface. Hot tea will sometimes increase the action of aperients, but it is doubtful whether it has any more effect than a similar quantity of hot water.

Roberts gives the following analysis of:

The Effects Of Tea And Coffee On Gastric Digestion

Digesting mixture: 2 grammes of dried beef fibre, 0.15 c. c. hydrochloric acid, I c. c. glycerin extract of pepsin, varying proportions of tea and coffee, water to 100 c. c.

Many elderly people find tea particularly grateful and soothing after reaching a period of life when the functional activity of the stomach is gradually weakened. A disproportion may exist between the quantity of food which the stomach can digest and the actual need of the body for nutritive materials to counterbalance the daily waste. In such cases tea enables the aged poor to live on less food than they would otherwise require, and is thus economical for them.

The refreshing effect of tea when taken into an empty stomach after bodily fatigue may continue between three and four hours, a period considerably longer than that of coffee or light wine.