Source

This beverage is prepared from the seeds of the coffee tree (Caffea arabica), which grows in many warm countries, though originally found in Arabia. The coffee berry is about the color and size of a ripe cherry, and contains two seeds placed face to face.

Active Principles Of Coffee

The active principles of coffee are essentially the same as those in tea. By the roasting process a volatile oil is liberated (called caffeol) to which the aroma is due. The caffein is chemically the same as in tea, and according to Hutchison (p. 310)., a cup of black coffee contains about as large a quantity of caffein and tannic acid as a cup of tea.

Effects Of Coffee

Coffee has only a slight retarding influence on salivary digestion, compared with tea, but an equally detrimental effect on gastric digestion.

As a stimulant it effects more directly the central nervous system; the heart action is considerably increased in rate as well as strength. Indirectly, this results in an increased activity of the kidneys. The respiration is deepened and the cerebral centers excited. For this reason it often proves useful in cases of opium and alcoholic poisoning. In some persons these effects are very mild; in others, they are severe, producing nervousness and insomnia, and coffee should be withheld. It removes the sensation of fatigue, for which reason it is used by many nurses when on night duty. It should never be given to children.

Coffee or tea taken with either milk or sugar alone is much more healthful and less likely to cause ill effects than when both are used.

Frequently after operation freshly made black coffee or tea without milk or sugar will be retained, and in some cases check vomiting. Give the patient one-half teaspoonful at frequent intervals.

Many preparations have been put upon the market as coffee substitutes, but they lack the aromatic oil and caffein for which it is really prized. They make, however, pleasing hot beverages, and served with sugar and cream, have a food value.