Lead has been supposed to act as an astringent; but, if astringents were useful, alum would be more effectual than any of the preparations of lead.
The vegetable acids have been considered as sedatives, and are generally employed in the cure of inflammation; but it would rather seem, as if they belonged to the class of agentes similes; for, in moderate quantities, they increase the appetite, &c. which no sedative, or agens dissimilis, ever does[13]: They also excite a general action, which is different from that induced by sedatives, and which is useful in curing many of the actions induced by these agents. We likewise find, that they are not serviceable, as local applications, in the cure of inflammation, unless in so far as they become the vehicle for applying cold. The surface is not very susceptible of their action; and, therefore, those who are inclined to continue their use, may do so without injury, and even with benefit, if they be cold; but then the same benefit will be derived from cold water.
Alcohol is likewise considered by some as a sedative, and introduced as a remedy, in the enumeration of those which are applicable in inflammation[14]; but, whatever its use may be in the inflammatio debilis, it must be allowed to be evidently hurtful in the inflammatio valida.
The last division of local application, contains those which tend, both simply to abate action in general, and also to excite, to a certain degree, a specific change of the action. Topical bleeding is the chief remedy belonging to this division. Bleeding with leeches, or the scarificator, is employed in two different circumstances: First, when we detract directly from the inflamed part; as, for instance, from the surface of a phlegmon: Secondly, when we detract only from the neighbourhood of the inflamed part; for instance, from the skin which covers an inflamed joint. When we employ topical bleeding, in the first case, we may suppose, that the aperture, and effusion from the extremities of the inflamed vessels, produces, to a certain degree, a change of action. Every action of the vessels is performed at their extremities, and the trunks and branches may be considered as canals subservient to the extremities, and which contract and dilate, in a degree proportioned to the general and local action. If, during health, we open a number of the extremities of these vessels, we induce the hemorrhagic action, which continues longer or shorter, according to circumstances, and which gradually terminates in a serous discharge, or secretion. If, during inflammation, we open a number of the extremities of vessels, either in the inflamed part, or immediately contiguous to it, we induce a similar hemorrhagic action, which is different from the inflammatory one, and, therefore, tends to diminish that action in the part. We likewise, by inducing the serous secretion, tend to produce a termination to the inflammatory action.
Topical bleeding will also, in part, operate, by simply abating the action, in consequence of the mere loss of blood; for, as the blood is withdrawn immediately, by different orifices, from the vessels of one part, that part, and those near it, may be supposed to suffer sooner, and to a greater degree, than the rest of the system. The branches which yield the blood, will even suffer considerably, for a time, although the loss of blood be very trifling, and produce no effect on the system. Thus, if one small artery be divided, we find, that, although the quantity of blood which flows from it be very inconsiderable, yet it is sufficient to produce evident changes in that vessel, making it contract, and become smaller, although the vessels in other parts be not at all affected. This depends upon the peculiar[15] action of the individual artery being affected[16], and the contracting state of the orifice, spreading along the branch and trunk by degrees[17], by which less blood is made to circulate through it. Bleeding from a vein, however, has not the same effect; because the quantity of blood in a part, is not so immediately dependent upon the state of the veins; and because veins are not the seat of much action. When we divide a small vein, we find, that it, by degrees, contracts, and transmits less blood, or closes completely; but the blood from the part does not circulate faster, nor is less blood sent to that part than formerly; therefore, topical bleeding from veins near the affected part, can have no great superiority over general bleeding.
The division, then, of a number of small arteries, may cure inflammation in two ways; first, by inducing a different action; secondly, by possessing the general properties of bleeding, namely, a simple diminution of action. The first will operate chiefly, when we apply the leeches on part of the inflamed portion. The second will operate, when we detract only from the immediate vicinity; and, in this case, the quantity of blood which is taken away, must be greater; because the effect has to be extended some way, the vessels not being in the inflamed part. The quantity must likewise be greater, because the effect depends entirely upon this; whereas, in the other case, it depended, in part, upon the peculiarity of the action which was produced.
The number of leeches which it is necessary to apply, will depend upon the violence of the action, and the place on which they are set; for, the greater the distance from the inflamed part, the more numerous ought they to be. It is therefore impossible to give any particular rule for the extent of topical bleeding. It may, however, be proper to observe, that we ought not to be satisfied with one application, more than with one venesection, for a general disease, but ought to repeat the local bleeding, whenever it may be necessary, although it may be twice or thrice in a day, founding our indications upon the same principle on which we use general bleeding. It is by a too sparing application of leeches, and their not being repeated sufficiently frequently, that we so often fail in removing inflammations, which, by a more active treatment, we might resolve. In general, the leeches ought to be applied as near the affected part as possible, or upon it. If, however, the seat of the inflammation be chiefly in the cutis, as in erysipelas, it will perhaps be more prudent not to apply them upon the spot; because the subsequent irritation is apt to increase the action afterwards, on account of the great delicacy of the part. There may even be some doubt as to the propriety of applying leeches to the vicinity of the inflammation; for the irritation of the bites may produce erysipelas in the part, or cause the original disease to spread.
The scarificator may be used where leeches cannot be obtained; but it is not so useful, when applied to the inflamed part, on account of the irritation which attends its application, and the cupping; but it is equally proper, where we detract not from the part itself, but from its vicinity.
Of the topical remedies, bleeding is the most powerful; and, next to that, cold solutions of lead. Where these cannot be employed, owing to the internal situation of the inflamed part, blisters must be used in their place.
Many other remedies used to be recommended, under the name of discutients, repellants, &c.; some of which have been formerly mentioned, when considering the ancient theories of inflammation; these, however, are now laid aside. But many practitioners still have an idea, that benefit will be derived from mechanically softening the parts by means of oils, or what they call emollients; and seem to consider, that poultices are chiefly useful for the same purpose; at least they only direct, that they shall be removed before they turn “stiff or hard.” But inflammation must be attributed to a different cause than increased attrition, and its cure must be effected by different agents from those which we employ for softening a piece of dead skin. Oils and liniments, in so far as they form a basis for other applications, or are used alongst with gentle friction, may be occasionally proper in the inflammatio assuefacta; but, in the inflammatio valida, they must be considered as absolutely useless.