Active Ingredients. - The active principles of the hop reside chiefly, though not exclusively, in the lupuline, which possesses the peculiar flavor of the hop, and determines, by its abundance or otherwise, the value of any particular sample. According to Payen, it contains two per cent, of volatile oil, about eleven per cent, of bitter principle, and fifty to fifty-five per cent, of resin. Tannin is present to the extent of about five per cent., also a nitrogenous substance and a gummy one.

The bitter principle, called lupulite or humuline, is yellowish-white, uncrystallizable, neutral and very bitter. It is soluble in alcohol, sparingly so in water, and insoluble in ether: it contains no nitrogen, and is destitute of narcotic properties.

The volatile oil is obtained by submitting lupuline to distillation with water: it is said to consist of an oxygenated oil and a hydrocarbon, C10H16, isomeric with oil of turpentine. In color it is pale greenish-yellow, though, when re-distilled, it becomes colorless. The taste is acrid; the odor resembles that of hops; it is very soluble in alcohol and ether, less so in water, and has a sp. gr. of 0.910. By keeping and exposure to the atmosphere it becomes a resinous mass.

The resin is bright-yellow, changing to orange color on exposure to the atmosphere. It is soluble in alcohol and in ether.

Physiological Action. - In regard to this very little can be said with any confidence. The general belief is that hops possess tonic and moderately narcotic properties; and that pain and nervous irritation may be allayed by the use of them, since they often assist sleep, if they do not actually induce it. The volatile oil has been stated to be narcotic; but this is denied by "Wagner.

Therapeutic Action. - Lupul ine is of value as a medicine for the relief of chordee, and for checking involuntary seminal emissions. It is said to be of use in nocturnal incontinence of urine, and in cases of irritable bladder.

Lupuline has been resorted to as an anodyne in rheumatism, and as a tonic in dyspepsia, and has been found serviceable in gouty spasm of the stomach.

With patients who suffer from insomnia, nervousness, or over-excitement, the hop-pillow is deserving of trial; it relieves pain and allays nervous irritation. It would seem as if the volatile oil must be the source of the influence.

Preparations and Dose. - Tinct. Humuli, 3 ij. - iv. (8. - 15.); Infus. Humuli,

Urticaceae The Hop Humulus Lupulus 49

, - iv. (60. - 1.20); Lupuhna, gr. v. - xv. (.30 - 1.); Tinct. Lupulinae, 3 j. - ij- (4. - 8.); Fl. Ext. Lupulinae, 3 ss. - j. (2.-4.); Oleoresina Lupulinae, gr. j. - v. (.06 - .30).