Caffeine is distinguished by containing more nitrogen than almost any other vegetable principle. It is absorbed unchanged into the circulation, and is a stimulant to the brain and heart, producing wakeful ness, with a clear, vigorous state of the intellect, and strengthening the contraction of the heart.

It resembles digitalis in its action as a cardiac stimulant, but acts more promptly and is more transitory in its effects.

It has no decided cumulative tendency, and does not disagree with the stomach. It acts as a diuretic by stimulating the cells of the kidneys, as well as by its action on the heart and circulation.

It has been known to cause, after doses of moderate size, nervous wakefulness and restlessness, tremulous-uess, frequent pulse, confused thought, and visions passing in a constant train. These symptoms have lasted for several hours.

In large doses it has caused poisonous though never fatal symptoms, such as muscular tremor, a burning feeling in the throat, palpitations with rapid, violent pulse and short, quick respirations; giddiness, nausea, disordered vision, and marked diuresis.

Average dose of caffeine, gr. iiss.-0.15 Gm.

Official preparations of caffeine are the Citrated Caffeine, Effervescent Citrated Caffeine, and Caffeine Sodio-Benzoate.