Coffee is one of the most extensively used articles in the narcotic group. The alkaloid which gives coffee its characteristic properties is caffein. Coffee also contains from three to four per cent of tannic acid. Other substances in coffee,, to which the pleasant odors and taste are due, are various forms of fats and carbohydrates, but these exist in such small quantities as to be negligible food elements. The effect of the caffein is that of a nervous stimulant, increasing the general nervous and mental activity. Coffee is frequently used to keep people awake. It is given as an antidote for opium poisoning because it stimulates the nervous system and prevents sleep. Coffee, when used habitually, produces various forms of dyspepsia, especially hypersecretion of hydrochloric acid, tannic acid being the provoking factor. The effect of coffee upon the nervous system is that of continued stimulation or excitation. Its continued use overworks and wears out the nervous system, thus causing a deterioration of both body and mind. If caffein were taken in a highly concentrated form, it would result in a narcotic habit quite as enslaving as the use of opium or cocain.

Effects of coffee-drinking.