Avena Sativa.—Common Oat.
Botanical Source.—Avena sativa, or the common oat, has a smooth stem, from 2 to 4 feet high, with linear-lanceolate, veined, rough leaves, with loose, striate sheaths; the stipules are lacerate; the panicle equal and loose; the spikelets pedunculate, pendulous, 2-flowered, both flowers being perfect, the lower one mostly awned; the paleae are somewhat cartilaginous, closely embracing the caryopsis; the root is fibrous and annual.
History.—Oats have been noticed by the ancient Greek and Roman writers; at present they are cultivated in nearly all northern temperate latitudes. Their native country is unknown, though they are stated to be indigenous in Sicily and in a certain Chilian island. When the seed is stripped of all its teguments, including its innermost, silky, fibrous covering it constitutes groats; and when this is ground into fine meal or flour it is called prepared groats. When the seed is kiln-dried, stripped of its husk and delicate outer skin, and then coarsely ground it constitutes the oatmeal of Scotland, a common, farinaceous article of food for laboring people and children (C). Many forms of "rolled oats" are now a general article of commerce, forming excellent cereal foods. Oats are largely in America as food for horses and cattle. American oatmeal is said to be inferior to the foreign preparations.
Chemical Composition.—Vogel found oats to contain 66 per cent of meal and 34 per cent of husk; the dried meal consists of starch, 59; saccharo-mucilaginous extract, 10.75; albumen, 4.3; oleaginous matter, 2; ligneous fiber and moisture, 24 (T.—C.). Other analyses have been made, which vary from the above in quantity and elements, showing oats to consist of a large proportion of starch, some sugar, gum, oil, albumen, gluten, a nitrogenous body, epidermis, alkaline salts, etc. M. Payen found oats to contain starch, 60.59 parts; gluten and other azotized matters, 14.39; dextrin, glucose, or congenerous substances, 9.25; fatty matters, 5.50; cellulose, 7.06; silica, phosphates of calcium, magnesium, and soluble salts of potassium and sodium, 3.25 (P.). A large proportion of the nitrogenous material consists of avenin, a body containing a large proportion of nitrogen to a small amount of oxygen (about 17 to 1). With solvents it behaves much like legumin, which it resembles. It may be obtained from oatmeal by treating the latter, at a low temperature, with a dilute solution of caustic potash, decanting the clear liquid and precipitating the impure avenin by means of acetic acid. To purify it wash it first with diluted alcohol; then, with concentrated alcohol, dissolve again in a dilute solution of potassium hydroxide, and treat again with acetic acid, when avenin will be precipitated (Kreusler).
Oatmeal.—AVENAE FARINA. Oatmeal is odorless, or has but little odor, is not so white as wheat flour, and has a somewhat bitterish taste. Particles of the integument may be observed in it, and it contains the gluten of the oat. Its starch-cells are polyhedral, having a checkered appearance, and are usually aggregated into ovoid or subspherical masses, easily separable under pressure. It is insoluble in alcohol, ether, and the oils; but the first two remove an oleo-resinous matter from it. Water removes its nourishing principles when boiled with it.
Action, Medical Uses, and Dosage.—I. AVENAE FARINA. Oatmeal is nutritive and demulcent. Good in habitual constipation, but not in dyspepsia accompanied with acidity of the stomach. In the form of gruel, either salted or seasoned with sugar, honey, or the pulp of fruit, it is an agreeable nutritive during convalescence from acute diseases, in the puerperal state and in some chronic diseases. Ɣ Oatmeal made into a cake with water, baked and browned like coffee, then pulverized and made into a coffee, or infusion, forms a drink which will allay nausea and check vomiting in a majority of cases when all other means fail, and used thus is very useful in diarrhoea, dysentery, cholera morbus, and irritable conditions of the stomach. One ounce of oatmeal in 2 quarts of water, boiled down to 1 quart and then strained, forms a very nutritive gruel. It may be rendered more palatable by the addition of vegetable acids, aromatics, sugar, prunes, raisins, etc.
II. AVENA SATIVA.—This plant is a nerve-tonic, stimulant, and antispasmodic. It ranks among the most important restoratives for conditions depending upon nervous prostration, and for the nervous exhaustion consequent upon typhoid and other low fevers, and the accidental disorders arising from these complaints, as weak heart, spermatorrhoea, insomnia, etc. In enfeebled states of the heart muscle it acts as a good tonic to improve the energy of the organ, and is recommended by Prof Webster to prevent relapsing cardiac rheumatism. In this condition it is not thought to be specially antirheumatic, but rather to strengthen that debility upon which the rheumatic diathesis depends, so that the patient is less subject to atmospheric and other impressions. In spermatorrhoea it is adapted to those cases of debility following adynamic diseases, or in simple spermatorrhoea when not due to self-abuse. The atonic state gives rise to a nervous erethism or an enervated condition favorable to nocturnal losses. In cases depending wholly or partially upon prostatic irritation it is of less value, but aids staphisagria, sabal, salix nigra aments, and other indicated remedies Spasmodic conditions of the neck of the bladder are said to be relieved by it.
A few years ago it was much lauded as a remedy to assist the morphine-consumer to throw off the habit, and to sustain the nervous system while undergoing that ordeal. We have, however, found it to exert but little good in this direction. A strong tincture may be prepared by crushing or pounding to a pulp the entire oat-plant when the grain is "in the milk," covering with strong alcohol and allowing it to macerate 14 days. The dose is from 10 to 30 drops in hot water; specific avena, 1 to 20 drops every 2 or 3 hours; Keith's concentrated tincture, 1 to 25 drops. This remedy was introduced by B. Keith & Co.
Specific Indications and Uses.—Nerve tonic, stimulant, and antispasmodic. Spasmodic and nervous disorders, with exhaustion; cardiac weakness; nervous debility of convalescence; spermatorrhoea from the nervous erethism of debility; tensive articular swellings.