(H. M. R.)
BELLABELLA, the common name (popularized from the Indian corruption of Milbank) for a tribe of Kwakiutl Indians at Milbank, British Columbia, including the subtribes Kokaitk, Oetlitk and Ocalitk. They were converted to Christianity by Protestant missionaries, and number about 300.
BELLACOOLA or Bilqula, a tribe of North American Indians of Salishan stock, inhabiting the coast of British Columbia. They number some 300.
BELLADONNA (from the Ital. bella donna, “beautiful lady,” the berries having been used as a cosmetic), the roots and leaves of Atropa belladonna, or deadly nightshade (q.v.), widely used in medicine on account of the alkaloids which they contain. Of these the more important are atropine (or atropia), hyoscyamine, hyoscine and belladonine; atropine is the most important, occurring as the malate to the extent of about 0.47% in the leaves, and from 0.6 to 0.25% in the roots.
Atropine, C17H23NO3, was discovered in 1833 by P.L. Geiger and Hesse and by Mein in the tissues of Atropa belladonna, from which it may be extracted by means of chloroform. By crystallization from alcohol it is obtained as colourless needles, melting at 115°. Hydrolysis with hydrochloric acid or baryta water gives tropic acid and tropine; on the other hand, by boiling equimolecular quantities of these substances with dilute hydrochloric acid, atropine is reformed. Since both these substances have been synthesized (see [Tropine]), the artificial formation of atropine is accomplished. Atropine is optically inactive; hyoscyamine, possibly a physical isomer, which yields atropine when heated to 108.6°, is laevorotatory.
Medicine.—The official doses of atropine are from 1⁄200 to 1⁄100 grain, and the sulphate, which is in general use in medicine, has a similar dose. It is highly important to observe that the official doses of the various pharmacopoeias may with safety be greatly exceeded in practice. They are based on the experimental toxic, as distinguished from lethal dose. A toxic dose causes unpleasant symptoms, but in certain cases, such as this, it may require very many times a toxic dose to produce the lethal effect. In other words, whilst one-fiftieth of a grain may cause unpleasant symptoms, it may need more than a grain to kill. So valuable are certain of the properties of atropine that it is often desirable to give doses of one-twentieth or one-tenth of a grain; but these will never be ventured upon by the practitioner who is ignorant of the great interval between the minimum toxic and the minimum lethal dose. It actually needs twenty to thirty grains of atropine to kill a rabbit: the animal is, however, somewhat exceptional in this regard. The most valuable preparations of this potent drug are the liquor atropinae sulphatis, which is a 1% solution, and the lamella—for insertion within the conjunctival sac—which contains one five-thousandth part of a grain of the alkaloid.
Pharmacology.—When rubbed into the skin with such substances as alcohol or glycerine, which are absorbed, atropine is carried through the epidermis with them, and in this manner—or when simply applied to a raw surface—it paralyses the terminals of the pain-conducting sensory nerves. It acts similarly, though less markedly, upon the nerves which determine the secretion of the perspiration, and is therefore a local anaesthetic or anodyne and an anhidrotic. Being rapidly absorbed into the blood, it exercises a long and highly important series of actions on nearly every part and function of the nervous system. Perhaps its most remarkable action is that upon the terminals of nearly all the secretory nerves in the body. This causes the entire skin to become dry—as in the case of the local action above mentioned; and it arrests the secretion of saliva and mucus in the mouth and throat, causing these parts to become very dry and to feel very uncomfortable. This latter result is due to paralysis of the chorda tympani nerve, which is mainly responsible for the salivary secretion. Certain nerve fibres from the sympathetic nervous system, which can also cause the secretion of a (specially viscous) saliva, are entirely unaffected by atropine. A curious parallel to this occurs in its action on the eye. There is much uncertainty as to the influence of atropine on the secretions of the stomach, intestines, liver, pancreas and kidneys, and it is not possible to make any definite statement, save that in all probability the activities of the nerves innervating the gland-cells in these organs are reduced, though they are certainly not arrested, as in the other cases. The secretion of mucus by the bronchi and trachea is greatly reduced and their muscular tissue is paralysed—a fact of which much use is made in practical medicine. The secretion of milk, if occurring in the mammary gland, is much diminished or entirely arrested. Given internally, atropine does not exert any appreciable sedative action upon the nerves of pain.