303. It is evident that a regular and healthy secretion of bile is indispensable to the act of chylification, and to the proper action of the intestines, and that a deficiency, redundancy, or a vitiated condition of this fluid may act as an exciting cause of indigestion. If it be deficient, the chyme cannot undergo that decomposition in the duodenum by which chyle is formed and separated; and as the bowels are, at the same time, deprived of their natural stimulus, the undigested mass is not protruded, but is left to undergo various morbid changes; air is extricated, the alimentary secretions become depraved, and the whole series of the digestive functions are thus suspended, or deranged. If the bile be too copiously secreted, it is poured out in large quantities into the intestine, producing temporary diarrhoea, and part of it being regurgitated into the stomach, during the act of vomiting, which, in the first instance, is excited by the sympathy of the stomach with the duodenum and hepatic system, occasions a train of symptoms of greater or less severity, according to the circumstances of each particular case.

If the bile be vitiated in quality, it will not only be incapable of accomplishing the alimentary change which it is destined to fulfil, but it will irritate and fret the mucous membrane by its contact. It is evident that the violence and extent of the symptoms produced by such causes will be liable to vary; and the practitioner must not imagine, that the absence of diarrhoea, colic, and other violent feelings, affords evidence of the healthy state of the biliary secretions. Derangements in these functions often proceed insidiously, and lay the foundation for a serious disease, which, although latent for a period, will ultimately be kindled into activity, whenever an exciting cause shall fire the train.

304. To explain the origin of biliary irregularities, we have to consider the sympathies by which the liver may be influenced. The investigation of the diseases of warm climates, and the corrected views, with regard to the autumnal complaints of our climate, have sufficiently established the existence of a sympathy between the skin and the liver. Whenever an organ has been in a state of over-excitement, it is liable to fall into a corresponding state of torpor. The perspiration is, therefore, more apt to be checked after the continuance of hot weather, than at any other season of the year; and since the same observation may be extended to the liver, we shall readily perceive the cause of those biliary affections which so generally occur in this country during the autumnal season. The application of cold to the feet, or whatever contributes to check the perspiratory functions, may create, in those predisposed to such complaints, a bilious attack. The sympathy which subsists between the stomach and liver has already been adverted to. It seems a wise provision, that the biliary function should be connected, by a close sympathy, with that of the stomach, in order that the food, converted into chyme, may meet with a necessary quantity of bile in the duodenum.

In consequence of such a sympathy, irritation in the stomach is generally attended with an increased secretion of bile; the action of nausea is usually followed by such an effect. Hence, melted butter, every thing fried, pastry, and other indigestible materials, are popularly denominated bilious; and although such a term countenances a latitude of expression, which is inconsistent with the more definite notions of strict pathology, yet it cannot be said to be erroneous. As the varied and increased action of a gland has much influence in determining the nature of the fluid secreted, we cannot be at a loss to explain the vitiated condition in which the bile is secreted under such circumstances: indeed it is frequently on such occasions of a degenerated colour, extremely acrid, and scarcely possessing the qualities of bile. Dr. Saunders considers it probable, that from the quantity secreted, and the rapid manner in which it is poured into the duodenum, there is not time sufficient for a perfect secretion.

305. We may therefore agree with Dr. Saunders, that whenever, either from an irregular distribution of nervous energy, or from the operation of indigestible and acescent food, the tone of the stomach falls below the degree necessary to the digestive process, the liver immediately sympathizes with it, and bile is no longer emulged into the duodenum, until a re-action takes place, when its quantity is morbidly increased in proportion to the degree of previous atony. If this occur to such an extent, that its free admission into the intestine be impeded, it will accumulate in the excretory ducts of the liver, and either regurgitate into the system by the hepatic veins, or be absorbed by the lymphatic system, and a yellow suffusion of the skin will follow.

306. The abuse of spirituous liquors, from their operation on the stomach and brain is a fertile cause of biliary derangement; and from the sympathy between the sensorium and the liver, the effects of strong and sudden mental emotions, in occasioning an irregular secretion of bile, will also admit of satisfactory explanation. I was lately called to a patient, who had become violently jaundiced in the space of three hours, in consequence of having received some intelligence which threw him into the highest state of consternation.