The direct effect of certain drugs upon the secretion of bile is unquestionable. Podophyllin, Rhubarb, Aloes, Colocynth, Colchicum, Jalap, Scammony, Ipecacuanha, Sulphate of Soda, Phosphate of Soda, and Chloride of Ammonium, Nitrohydrochloric Acid, and (non-officinal) Euonymin and Iridin, stimulate the liver substance and increase the amount of bile secreted, and are therefore direct cholagogues. Mercurials, including Calomel, as well as acids and such substances as Guaiacum, Sarsaparilla, etc., possibly act less powerfully as direct hepatic stimulants. Opium and Morphia reduce the activity of the secretion.

III. Pathological Relations

The therapeutics of the liver will be best illustrated by a study of the treatment of its functional disorders. The common causes of derangement of the liver are to be found in the materials supplied to it, namely, food and air, and especially in the want of due proportion between the two. Most frequently there is excess of food-excess of rich food, especially of meat and alcoholic drinks, causing also primary indigestion. On the other hand, there may be imperfect oxygenation of the blood supplied through the hepatic artery, i.e. deficient respiration and circulation, generally referable to sedentary or luxurious habits, abstinence from muscular exercise, and confinement to ill-ventilated hot atmospheres. Not uncommonly the two classes of causes are combined, as is well seen in the disorders and diseases of the liver so common in the tropics.

Another way in which disorders of the liver originate is through retention of the products. If the kidneys, lungs, or bowels are inactive, the liver will be blocked, as it were, by urea, uric acid, sugar, and bile; and hepatic metabolism will become feeble. This condition is generally referable to impaired muscular and circulatory activity; to want of exercise, air and light, which beget renal and intestinal torpidity: it is the disorder of town life. In other cases debility of the liver is distinctly inherited.

In whatever way induced, derangement of the liver consists in certain disturbances of the chemical processes within it, which manifest themselves by altered composition of the excretions and many well-marked symptoms. The urine contains an excess (rarely a deficiency) of urea, an excess of uric acid, occasionally sugar, and even albuminous bodies, derived probably from the liver; whilst its reaction is disturbed, the colouring matter is in excess, and leucin and tyrosin make their appearance in it. The bile is altered in quantity and quality, giving rise to diarrhoea oTconstipation with foul pale stools, to inspissation of bile in the ducts and gall bladder, and the formation of gall stones. The general symptoms of biliary disorder are referable to the circulation in the blood of an excessive amount of the normal products-urea, uric acid, etc., and of imperfectly formed products allied to these. Such products of disordered metabolism, though differing from the normal only by a few atoms, or in the arrangement of their atoms, may be highly deleterious in their action on the body. Entering the blood by the hepatic veins, they disturb the nervous system, and are the cause of the sleepiness, languor, irritability of temper, the headache, and the general misery and melancholy, so familiar in the "bilious." They enter the muscles and produce aching, weariness, muscular debility, and trembling. Palpitation and flushing indicate their action on the circulation, whilst the general nutrition also suffers. If this condition persist, certain chronic states of the system are induced, which are known as gout and lithaemia. The heart and vessels become diseased, as well as the skin and joints. Continued disturbance of the reaction and constitution of the urine leads to a deposit in the urinary passages of some of its salts in a solid form, constituting gravel or calculus; and structural disease of the kidneys may ultimately result.

Absorption of bile into the blood may occur in these cases, but more so in actual plugging of the ducts, which leads to jaundice. In either case, some or all of the constituents of the bile enter the blood, circulate with it, colour all the organs, and are cast out in the various secretions, especially the urine.

Lastly, the glycogenic function of the liver may be disordered, and sugar make its appearance in the blood, urine, and all the tissues, constituting glycosuria or diabetes mellitus. Excess of sugar-yielding food may cause this, as we have seen, but well-marked diabetes is generally referable to derangement of the elaborate nervous and chemical processes of storing and re-distributing the nutrient elements of the food carried on in the liver. Hunger and wasting are therefore its prominent symptoms, and thirst is also very urgent from the diuretic effect of the sugar. In some instances diabetes may be traced to injury or disease of the hepatic ("diabetic") centre in the brain, or of the nervous connections between it and the liver.

IV. Natural Recovery

Disorder of the liver disappears under favourable circumstances; that is, with a return to the normal influences. Eecovery is assisted, on the one hand, by temporary abstinence from food, brought about by loss of appetite, or even loathing for food; and, on the other hand, by excretion of the morbid products. Excess of bile relieves itself naturally by bilious diarrhoea. Nature requires guidance, however, in hepatic disorders, for the languor, depression, and muscular debility which it originates tend to give rise to further indisposition to exercise, and thus to an aggravation of the Evil.

V. Therapeutics

Hepatic disorder can only be prevented by taking a comprehensive view of the relation of the liver to the organs of digestion, absorption, blood-formation, and excretion. The income in the way of food and air must be thoroughly supervised. The diet must be definitely ordered. Perfect digestion and intestinal activity must be secured. In many cases it is found that when this has been done, little more is required. Abundant bodily exercise must be recommended. The atmosphere breathed must be as pure, cool, and bright as possible. Sedentary or lazy habits must be changed for wholesome exercise in the open air, in the form of walking or riding. In the class of cases of disordered liver constantly met with in large towns, change is essential from the foul hot dull atmosphere of the workshop and dwelling, to the pure air of the parks or of the country. But the beneficial effect of exercise on the liver is not to be estimated solely by the amount of oxygen admitted. It will also be evident in increased activity of the kidneys, skin, and bowels, all of which will unburden the liver by hastening the removal from the blood of metabolic products.