The Action of Medicines in the System / Or, on the mode in which therapeutic agents introduced into the stomach produce their peculiar effects on the animal economy

by Frederick William Headland

The inflammatory process—the chief seat of which, however it may first originate, is in the circulating blood—exerts a powerful influence over the nervous system, and may, by this influence, cause death. When fever is produced to any extent, there must be danger.

We are enabled in two ways to control or to mitigate this state of things. We may produce an action on the nervous system, or we may direct our attention to the process in the blood.

Of Neurotic medicines, which we shall have to consider hereafter, there are some which may be made use of at the commencement of the attack, and others which are appropriate when the process is more advanced. Of the first kind is Antimony, considered in its Neurotic action. Employing it in large doses, we may produce a powerful effect upon the nerves which supply the heart, and thus, by diminishing the impulse upon the inflamed parts, or on the vascular system generally, promote absorption and resolution. Blood-letting produces the same action, but in an inverse mode. Antimony diminishes the pressure on the vessels by weakening the force of the heart; Blood-letting weakens the force of the heart by diminishing the pressure on the vessels.

Such Neurotics as Opium are employed at a more advanced stage, when the inflammation cannot be suddenly put a stop to, and our object is to counteract the effects it has produced. Besides relieving the pain and nervous irritation which are so much to be dreaded, Opium may be employed to prevent a blood-medicine from passing out through the bowels. Antimony and bleeding are appropriate in sthenic cases. Opium should not generally be employed in these instances, nor should it be given in brain disorders, or in any case where there appears to be a determination of blood to the head.

Certain medicines of the class of Eliminatives, and certain Catalytic remedies belonging to the present order, are employed to counteract the inflammatory process in the blood.

Of the former, the most important are Purgatives and Diaphoretics. By diminishing the amount of the serum of the blood, they not only tend to check effusions, but act indirectly on the heart, in the same way as the medicines last spoken of; and they probably also promote the passage of morbid or of peccant materials out of the system through the glands. Acid and saline drinks may act as Diaphoretics, besides exerting each a peculiar influence in the fluids.

Of this Catalytic order, Antimony and Mercury are those which tend most powerfully to check the general blood-process of inflammation. The former is used in urgent and acute cases to make a sudden and powerful impression, adding to its Hæmatic action a sedative effect on the heart and circulation. Mercury exerts no such immediate influence. Diminishing the Fibrine of the blood, and having other operations of a peculiar kind in this fluid, it powerfully promotes absorption and counteracts effusion, in all inflammations. The blood-action of these remedies, though not positively slow, is slow when compared to an action on nerve. Thus when Antimony is given in large doses, as is desirable in some highly sthenic and dangerous attacks, its blood-action is lost in its immediate Neurotic operation.

So that in Croup and Pneumonia, both rapid and fatal inflammations, Antimony is far preferable to Mercury. But in Pleurisy—where there is generally no immediate danger to be dreaded, but a subsequent effusion, Mercury is best, being in time to lessen or to prevent this result.

From the action of both on the blood, and one on the nerves, these are very lowering remedies. In the employment of Antimony in fevers and inflammations, the production of nausea generally indicates that it has taken sufficient effect; but it may sometimes be better to give such a dose as shall cause vomiting, especially when a violent counter-irritant action is to be desired. The increase in the quantity of saliva, and slight soreness of the mouth, which result from its action, will show when the administration of a Mercurial has gone far enough. It is seldom advisable to cause copious salivation.

Alkalies dissolve the Fibrine of the blood, and appear by this to lessen its deposition, and retard its formation. Thus, when given in large doses, they operate as Antiphlogistics. They have sometimes been employed with advantage in fevers of the acute or sthenic kind. Exerting an influence over the inflammatory process considered per se, Alkalies and Mercurials are more particularly efficacious in some special varieties of inflammation, because in such cases they further counteract the morbid agency by which the process is excited and kept up.