The synergistic action of remedies is the superstructure of most of our medical prescriptions. Its action is co-operative with the principal agent you may have decided to employ. There are accessory, or secondary substances which act the part of medical adjuvants. These substances serve, for instance, to aid in the solution, transformation, and chemical metamorphoses of the substances destined to be absorbed, and consequently favor their absorption. Thus, acids serve to favor the solution of bases, and reciprocally the bases that of the acids. Another condition in which secondary or accessory substances may add something to the effect of the principal substance, is, when these ingredients, although having less effect than the principal substance act exactly in the same manner, and are true synergies, adding to the effect of the principal substance. † The physiological force of a remedy is not always a factor in the character of a synergistic. Even water may serve as such. For example: the physiological action of water internally, is to hasten the metamorphoses of tissue, and increase the urinary and cutaneous secretions. Its action upon the kidneys and bowels is increased by salines, upon the skin by sulphur, upon the blood by iron. ‡

The synergia of a substance may be applied to augment the power of the basis in a formula, or to make more acceptable its effects. Under this principle morphine and atropia, or opium and belladonna are combined in the treatment of pain. Guarana, in a cup of strong tea, for headache. Canabis indica, with bromide of potassium, in insane delirium. § The sulphate of iron to increase the purgative powers of aloes, § or to combine ipecac with aloes to prevent its irritating effects upon the anus. Camphor has a wide range as a synergistic - with opium in the treatment of diarrhoea and other diseases - with aloes to render its action more certain and less irritating - with cantharidin it renders protection to the kidneys. Nearly all the narcotics unite with characteristic effects. Conium and hyoscyanus have an action of their own; the same with opium and conium, and conium with belladonna. The combination of opium and hyoscyamus is said to form the most powerful of narcotic combinations.

*Prof. Potter.

‡ Prof. Robert T. Edes.

§ Waring.

†Prof. Adolph Gubler.

Harley.

The protective synergia characterizes many of our medical formulas, as forcibly illustrated by uniting carbonate, or spirits of ammonia, with iodide potassium, to prevent or control the symptoms of iodism. Chloral to moderate the violent effects of strychnine, and even to serve as an antidote to its poisonous effects. The same might be said of opium, to hold in check the toxic force of veratria. Sometimes this class of synergia is given alternately with some powerful remedy; as when ammonia is administered by inhalation during chloroform-anaesthesia to prevent heart failure.

Sometimes a synergistic alone may determine the physiological effects of a remedy. Digitalis may fail to act as a diuretic until combined with bicarbonate of ammonia, or with squills. The infusion should not be chosen as a cardiac remedy, nor the alcoholic preparation when diuretic action is desired.* Even the infusion of digitalis, prepared from the fluid extract, as a rule, may be devoid of diuretic effects.*

There is hardly any more interesting and more important feature in the practice, than the use of synergiae to aid the physiological resistance, in preventing dangerous complications in formidable diseases. Prophylactics, in the common sense, might be included, but here we take it from a different standpoint. In typhoid fever there may be a fatal tendency by the intervention of pneumonia, or perforation of the intestines. In adynamic malarial fever, of hemorrhage. In many forms of malignant fever by excessive vomiting, etc. In such diseases, in particular, when of an epidemic form, a synergistic treatment should be enforced at the earliest stage of the disease. You, really, must prescribe for, what you may expect to happen in the future. For, to prevent pneumonia in typhoid fever, give ipecac for the first cough, slight as it may be, and at the same time to protect the bowels from ulceration, without waiting for any unfavorable symptoms to come. In epidemic diseases, where hemorrhage is usually a fatal complication, give turpentine at the very beginning of the disease, and do not wait for the bleeding, which nothing then can stop, as it usually goes hand in hand with collapse. By this system of medication the patient can be often fortified in synergism with the regular treatment of many serious diseases with the happiest effects.

In an epidemic of a malignant form of typhoid fever that raged in central Illinois, nearly all the fatal cases died from the effects of an uncontrollable hemorrhage of some kind. In consultation I advised that cases of fever of recent occurrence be put on haemostatics, as gallic acid and turpentine, synergistic to a sustaining treatment, with the happy result of no further loss of a single patient. † In an epidemic of malignant gastritis (following an epidemic of erysipelas) in central Ohio, it appeared that excessive vomiting tended to the fatality of the disease. In consultation, muriated tincture of iron with hydrocycanic acid were recommended to be given to head off the vomiting. The remedy mitigated the disease at once, and even in advanced cases recovery ensued. † Special pains seems, in place, here to impress upon medical readers the importance of this question, involving as it does the golden rule: "It is better to prevent than to cure."*

*Dr. F. A. Castle.

†Dr. G. P. Hachenberg, Cincinnati Medical News, 1880, p. 600.