When an actual instance of metabolic disorder demands treatment, we must first attempt to discover its cause, and to remove it by the same measures which might have prevented it. Thus the cause of gout may be swept from the system in many instances by a timely and thorough reform of the diet, and stimulation of the bowels, liver, and kidneys by a combined cathartic and cholagogue, followed by a saline, as recommended under the head of the Liver. Lead poisoning may be cured in the same way, by hastening the excretion of the metal by Iodide of Potassium. When these or other disorders of metabolism, such as rheumatism, syphilis, and tuberculosis, have become chronic, great benefit is derived from change of air and treatment by natural baths. We can sometimes remove fatty degeneration, that marked instance of imperfect metabolism, by removing its cause-an imperfect blood-supply, local or general, e.g. by Iron. In other cases we may attempt to destroy, if we cannot remove, the cause; thus it is possible (but not certain) that Mercury partly cures syphilis by directly destroying its virus; Quinine malaria; and Salicin rheumatism.

As a rule, however, in the more pronounced, the so-called specific, forms of disordered nutrition, such as tuberculosis, cancer, and syphilis, all that we can do is to counteract the cause, and relieve or remove its effects; that is, to treat symptoms. The specific fevers, such as typhoid and scarlatina, must be similarly treated symptomatically, for their course cannot be arrested. The pyrexia is combated by febrifuges or antipyretics, which we shall discuss fully in another chapter; the waste is repaired by nourishment; and other symptoms are relieved as they arise. Inflammation and its effects-abscess, effusions into cavities, growths, adhesions, and so on-will be treated by local stimulants or alteratives, such as poultices; friction with alcoholic, aromatic,and oily preparations; douching, baths, blisters, etc., to which we shall return in chapter xiv (The Body Heat, And Its Regulation : The Skin).; or they may demand surgical interference. In other kinds of metabolic disorders, such as tuberculosis (phthisis, consumption), we have to direct a considerable part of our treatment to the maintenance of the general nutrition, by preserving digestion, and giving highly-nutritious foods, such as Cod-liver Oil until the process has temporarily spent itself, and ended possibly with the evacuation of the diseased parts.

The question of the treatment of syphilis, chronic gout, rheumatism, and a number of local diseases probably related to these, for example, of the skin, joints, and nervous system, introduces us to the use of alteratives. We saw that alterative drugs act by exercising the tissues, and we have now to point out how exercise benefits an organ actually the seat of disease. For instance, syphilis is characterised locally by masses or patches of small-celled growths, with peculiar anatomical relations, proceeding probably to ulceration, that is, to death of the part. How do Mercury and Iodine remove these growths and thus cure the syphilis ? In answer to this question it may be said that there are two ways in which it may be desirable to exercise tissues. First, there may be need of increased metabolic change in order to remove excessive growth. Mercury and Iodine act, partly at least, in this way upon syphilitic growths. They hasten the life-processes of the young cells so much, that the cells disappear in the form of products, or, as it is commonly expressed, "are absorbed." It is essential to the success of this plan of treatment that the alterative substances should be thoroughly under control, and, as we have seen, that abundant food and air be ingested to prevent failure of nutrition.

Secondly, there is an effect of exercise beyond an increase of work accomplished: work that is increased in amount can be changed in kind; exercise is beneficial, not only to the indolent individual, but to the vicious. So with the tissues. Exercise may bring them into a new, a normal, state of function, when they have been deranged or even diseased. In order to get the tissues to work normally, we must get them to work somehow, knowing that such work means chemical change, or even active nutritive renovation of the elements. The natural disposition which all tissues inherently possess to return to the normal, is thus afforded an opportunity of coming into play; and the result is, not a mere increase of activity, but also an alteration in kind of the activity. Henceforth the protoplasm, if supplied with an abundance of food and oxygen, itself returns to the normal state. This powerful effect of alterative drugs is seen in such diseases as chronic gout, skin diseases, rheumatism, and disorders of the nervous system. Besides Iodide of Potassium, the alteratives used for this second purpose are chiefly Arsenic, Silver, Antimony, Phosphorus, and occasionally Copper and Zinc. Sulphur is a mild alterative, valuable in rheumatism and skin diseases, especially in the form of natural waters. Many-vegetable substances are credited with like properties, notably Sarsaparilla, Guaiacum, Hemidesmus, Serpentary, and Mezer-eum, but the physiological action of these is very obscure, and their value as medicines doubtful.

Substances which increase Metabolism.

Alteratives.

Substances which diminish Metabolism.

Local Stimulants. Local Alteratives.

Hydrargyrum

Oleum Morrhuae.

Cadmium

Ferrum

Oleum Olivae

Iodum

Antimonium

Glycerinum

Sulphur

Phosphorus

Alcohol

Water

Arsenicum

Quinia

Fixed Oils

Sulphur

Salicin and Salicylates

Alcohol

Calcii Sulphidum

Resorcin

Aether

Calcii Chloridum

Chinolin

Chloroforraum

Calcis Hypophosphis

Kairin

Ammonia

Sodae Hypophosphis

Volatile Oils

Water

Oleo-Eesins

Guaiacum

Resins

Hemidesmus

Balsams

Mezereum

Sarsa

Caff in

Guarana

Coca