With respect to the other kinds of Dropsy, we have already given an account of Hydrocephalus among the diseases affecting the head ; for although it may be cor rectly placed among the Hydropes in a nosological sys tem, yet, in a pathological and practical point of view, it more properly comes under the Neuroses. The Hy drops pericardii is a disease, the existence of which it is difficult to ascertain before death, and for which we have no appropriate remedies, while the other genera that have been enumerated, so far as their treatment is concerned, fall under the province rather of the surgeon than of the physician.* We have made the various diseases of the skin the fourth order of the Paratrepses, an arrangement which vve arc induced to adopt, because we regard them as, for the most part, proceeding from, or depending upon, a mot bid condition of the body, connected with a defect of some of the functions either directly or indirectly con cerned in the process of nutrition. Some of them are, no doubt, entirely local in their origin, and remain so during the whole of their progress ; but in the general view which we are now taking of the subject, it would not be practicable to attend to these minute distinctions, nor indeed is the limit between those that are strictly local, and such as exercise a more general operation over the body, drawn with that exactness, as to enable us, even with every degree of attention, to determine to which class many of the individuals may belong. In a nosological system, which is exclusively appropriated to the consideration of cutaneous affections, it is neces sary to introduce every complaint of the skin, although it may appear to be only one symptom, and that perhaps the least important of a number of others that constitute the disease ; but in a more general arrangement, we place many of the eruptions, as Small-pox, among the Exanthemata, or in other classes, according to the na ture of the circumstance that gives their distinguishing character. In a practical point of view, the most per fect arrangement of cutaneous diseases would be deriv ed, not so much from their visible form, whether they presented the appearance of pimples, vesicles, ulcers, &c. as from a combination of those circumstances which might throw light upon their scat, or their proximate cause. We are, however, altogether unable to accom plish this, except in a few instances, and therefore we must have recourse to a more technical method of class ing them according to their external characters. The most scientific arrangement upon this principle, is that in which the cutaneous affections are distributed into eight genera, according as they essentially consist in pimples, scares, rashes, blebs, pustules, vesicles, tuber cles, or spots. It would be obviously inconsistent with the nature and object of this work, to enter into a minute examination of all the various modifications which these diseases assume, or even to describe them individually in their more ordinary forms. Indeed, the management of them may almost be considered as a separate depart ment of the art, like that of surgery, and as not falling under the cognizance of a general treatise on the prac tice of medicine. 'We shall, therefore, aim at nothing mote than to offer a very few remarks, relative to the general principles upon which we treat these com plaints, without descending to a separate enumeration of them.
In the first place, exclusive of those cutaneous dis eases which essentially consist in Fever, and of which the eruption is only an accompanying symptom, such as Small-pox and Measles, we may consider them as be longing to the two great divisions of acute and chronic, or, what amounts nearly to the same thing, of such as are constitutional, and such as are local. The first of them conic on suddenly, and produce some disturbance of the functions, and after running through a regular course, manifest a tendency to a spontaneous cure ; the second come on gradually, continue for an indefinite length of time, disappear, and again make their appear ance in an irregular manner, and this without necessarily producing any constitutional action, or being accom panied by any change in the state of the functions. A second important circumstance respecting cutaneous diseases is, whether they are contagious or not ; the greatest part of them are certainly not so, but there are others which exhibit this property in the most marked manner, and which it is therefore necessary for us to guard against in our management of such cases. In the 3d place, some cutaneous diseases are obviously heredi tary, the children of those who have been affected by them having a peculiar tendency to such affections. In the 4th place, different cutaneous diseases are observed to attach themselves especially to different pet kids of life, some being confined to childhood, others appearing more commonly about the period of puberty, and others again in old age. In tne 5th place, the habits of life, especially with repect to exercise and temperance, the nature of the employment, local situation and climate, and many other circumstances, both external and inter nal, have a very powerful influence in the production of cutaneous diseases; and the same may be observed with re spect to the state of society, and the degree of civiliza tion, which, except in a few instances, where there has been too much indulgence in the luxurious gratifica tions of the palate, tends most materially to diminish the violence, or even altogether to annihilate some of the most loathsome of them. Independent of all these circum
stances, there are causes which we are quite unable to comprehend, from the operation of which certain affec tions of the skin prevail at certain periods, and afterwards become nearly extinct, in this respect resembling various other classes of diseases, in which these alternatiops of increase and decline are not unfrequently observed, and which are equally difficult to refer to any assignable cause.
In the cure of cutaneous diseases, the first point to be attended to is, how far we are to employ general reme dies, or how far we are to rest satisfied with mere topi cal applications. Probably, in a great majority cf in stances, they will both of them be necessary. There are, indeed, some of these affections which may be cured solely by topical remedies, while, on the contrary, there are others which require only constitutional treatment. The general remedies may be classed under the heads of those that tend to diminish febrile excitement, of purr gatives, sudorifics, and tonics, to which we must add specifics, those which cure the disease without produ cing any sensible effect, which we can refer to a gene ral principle. In applying these remedies, we must ob viously select them according to the supposed necessity of the case. 'We inquire whether there be any febrile excitement, any torpor of the bowels, dryness of the skin, defect of appetite, or general weakness, and we then use the appropriate remedies. The local remedies for cutaneous affections may be arranged under the heads of stimulants and sedatives, those which excite or diminish the action of the vessels of the skin ; emolli ems, those which mechanically soften or relax the parts; and here also, as in the former case, we must introduce a class of specifics. Of the existence of a class of re medies, which have the power of stimulating the skin when applied to its surface, we have sufficient evidence ; but there is considerably more difficulty in clearly dis tinguishing the action of sedatives ; and when we wish to produce this effect, it is generally accomplished in an indirect manner, or simply by the removal of some sti ntulating cause. The circumstances which direct our judgment in the choice of remedies, are derived patty iron' inquiring whether the symptoms indicate an excess or a defect of action in the part, and partly by tracing an analogy between the disease under consideration, and others, with the treatment of which we are better ac quainted,—a kind of practice, it must be confessed, which is often very empirical, and the result of which is very uncertain. Of this uncertainty we have the most convincing evidence in the writings of those, whose judgment and information on these topics is held in the highest estimation ; for we find that they proceed prin cipally upon the experience that is derived from insu lated facts, and that they frequently recommend, for the cure of the same disease, remedies that appear to be of the most opposite nature, in the selection of which we have very little explicit direction, but are recommended to try them in succession, and to adhere to that which ap pears to be the most beneficial. Upon the whole, we may conclude, that whatever promotes the general health must be always favourable to the relief of these diseases, and in many cases will effect a cure ; that, for this pur pose, it is of the highest importance to obtain a healthy state of the digestive functions, and that temperance, fresh air, exercise, and purgatives, are to be regarded as the basis on which we are to proceed, and which will materially assist us in the future progress of the cure. Upon this principle, we shall be at no loss to account for the benefit that is obtained from purgative saline waters, and when they contain sulphur, which has a decided claim to be considered as a specific in certain cutaneous diseases, they present us with the most effectual reme dy for some of these affections. Calomel has been very generally employed in these cases, and there can be no doubt of its frequently proving highly useful; but we should be disposed to refer its good effects to its action as a purgative, or at least to the power which it exer cises over the organs that are concerned in the pro cesses of digestion and assimilation. We have but little confidence in most of the boasted specifics for cutaneous diseases; they are generally given after the exhibition d'f more active remedies, if not in conjunction with them. Their operation, even as admitted by their advocates, is slow, and unattended with any sensible effects, and they arc commonly prescribed in connexion with some system of regimen, or with sonic change in the occupation or mode of life, to which we may, with more probability, refer any advantage that is gained. We must, however, make an exception in favour of sulphur, of the efficacy of which no one can doubt, and the same remark may be also extended to arsenic, and probably to iron, but of the nature of their operation we do not presume to offer any opinion. As to the whole tribe of stimulants, both the various chemical preparations, acids, alkalies, me tallic oxides, and salts, as well as the acid vegetable substances, we have little to observe in the way of gene ral principles, how far any of them ought to be regard ed as possessing specific virtues, or whether they dif fer from each other solely in the degree of their stimu lating power, or in their mechanical properties, we do not feel competent to decide.