VOMITING consists in the stomach emptying itself through the gullet and mouth. It is preceded by a feeling of nausea, a flow of saliva in the mouth, and the breaking out of perspiration; the countenance grows pale, a feeling of weakness spreads over the whole body, and the pulse becomes slow. At last the muscles of the abdomen and the diaphragm strongly contract, and the whole contents of the stomach are ejected with greater or less violence. The first matters to be ejected are the food and drink present, then mucus from the stomach and esophagus, and lastly, bile from the duodenum. In cases of disease, abnormal substances are sometimes vomited, such as blood, fragments of the intestines, and even excrementitious matters. When the vomiting is over it is foll9wed by languor and drowsiness, or, if the excitement was inconsiderable, the usual state immediately returns.
The causes of vomiting are various. In the first stages of infancy it is almost nor mal, and occasions no disturbance of the system. In many animals, too, it is a normal function of life, as when birds of prey reject the hair and feathers of their victims. The infant gets rid of the superabundant milk it swallows by throwing it up with no trouble. Some persons can excite themselves to vomit by swallowing air.
The immediate causes of vomiting may be reduced, according to Dr. Carpenter, to the three following categories: "(1) The contact of irritating substances with the mucous membrane of the stomach itself; these, however, cannot act by direct stimulatiom upon more than its own muscular coat; and their operations upon the associated muscles must take place by rejlexion through the nervous circle furnished by the pneumogastric and the motor'nerves of expiration. (2) Irritations applied to other parts of the body, likewise operating by simply-reflex transmission; as in the vomiting which is consequent upon the strangulation of a hernia, or the passage of a renal calculus; or in that which is excited by the injection of tartar emetic or emetin into the circulating current, when these,substances probably produce 'heir characteristic effect by their operation on the nervous centers. (3) Impressions received through the sensorial centers, which may be either sensational or emotional, but which do not operate unless they are felt. In this mode seems to be excited the vomiting that is induced by tickling the faeces, which first gives rise to the sensation of nausea; as well as the vomiting consequent upon dis gusting sights, odors, or tastes, and upon those peculiar internal sensations which are preliminary to sea-sickness. The recollection of these sensations, conjoined with the
emotional state which they originally excited, may itself become an efficient cause of the action, at least in individuals of peculiarly irritable stomachs, or of highly sensitive nervous systems."—Principles of Human Physiology, 6th ed., p. 77.
According to the oldest doctrine respecting vomiting, it was held to arise solely from convulsive movements of the stomach, which was thought to take on a motion contrary to the usual peristaltic motion. Bayle advanced the opinion, that the stomach is quite passive in the operation, and that its contents are emptied entirely by its being com pressed through the contractions of the abdominal muscles and the diaphragm. An apparently conclusive experiment of Magendie's, in which the stomach was removed, and a bladder substituted for it, had more recently (in 1813) satisfied most physiologists as to the passiveness of the stomach in vomiting, until Be'clard and Budge showed the msufliciency of his experiment. It is found, in fact, that in vomiting there aretwo sets 1 actions, viz. (1) contractions of the abdominal walls, while the remains fixed, and forms a support to the stomach, and (2) the stomach itself performs jerking movements, the pylorus, or inferior orifice, at the same time closing, while the cardiac sphincter relaxes, without which last-named action vomiting is impossible; and that either of the two kinds of movement—the abdominal or the stomaehal—may eject the contents of the stomach into the gullet.
In the treatment of vomiting, we must consider it as a symptom rather than a malady. Where the stomach is irritated, relief is afforded according to circumstances, by drinking cold water, aerated or soda water, or, if necessary, by opium or nux vomica. Cold applications outwardly also do good. In other cases, infusions containing ethereal oils —camomile, coffee, etc.—astringents, or correctives for acidity—magnesia, soda, etc.— are the fitting remedies. When the irritation is in the brain, the best remedy is a hori zontal position, with composure and darkness.. If a person in sound health is suddenly seized with vomiting poisoning may be suspected.