GEN. I. SPEC. I. Apostema commune. Common aposteme. That pus is a distinct secretion, B. Bell's valuable treatise on ulcers *; and most of all (to the present author, at least, most of all) that his friend Dr. Parr, with all the light of his contemporaries before him, should have offered it as his own opinion, in his elaborate and upon the whole very excellent Medical Dictionary; in which he tells us, after M. Gaber, that the pus of an abscess "consists of the substance of the vessels, and of the cellular membrane dissolved in the serum." That pus, instead of being a mere solution of dead animal matter, is a distinct and peculiar secretion, is now notorious in known to most practitioners from personal observation, the present day. Often found where it can be no thing else. illustrated. who must have witnessed it repeatedly in situations in which there has been no ulceration or breach of structure, and consequently where there could be no dead animal matter to dissolve. It was noticed in this form by De Haen so far back as the middle of last century; and was pointed out by Mr. Hewson as frequently found, on dissections, on the surface of the pleura, the peritoneum, the pericardium, in a Still further perfectly genuine state. A very decided case, to which both Dr. Hunter and Mr. J. Hunter were witnesses, was published by Mr. Samuel Sharp about the same time that De Haen first brought the subject before the public. Nothing is more common or more copious than the secretion of pus without ulceration in the first stage of purulent ophthalmy, and in purulent inflammation of the mucous membrane of the glans penis; and I remember having attended about twelve years since a gentleman in Bedford Row, who had irritated the urethra by improperly introducing a bougie into the bladder, and about three days afterwards discharged with his water not less than half a pint of pure pus, which separated itself from the water, and subsided, and thus gave me an opportunity of examining it minutely. I requested Mr. Cline's attention to this case, and we saw not the slightest reason for suspecting any ulceration whatever. Singular discharge of pus from the urethra. Part L. Sect. iii. eye GEN. I. SPEC. I. Apostema Common aposteme. Genuine pus is peculiarly distinguished by its consisting of white globules swimming in a fluid, which to the has the appearance of serum, but possesses charac- commune. ters of its own, equally different from those of serum and of every other secretion we are acquainted with; and Distinctive which render it coagulable in a saturated solution of mu- character of genuine pus. riate of ammonia, which is its specific test. Pus, however, is not globular at its first formation, but a transparent fluid of a consistence in some sort resembling jelly; the globules are produced while it lies on the surface of the sore, usually, when not exposed to external air, in about fifteen minutes after its secernment. The perfection of pus seems to depend upon the large proportion which its globules bear to its other parts. It is specifically heavier than water, and approaches nearly to that of blood. It has a sweetish, mawkish taste (apparently from its containing sugar), very different from that of most other secretions. After putrefaction it evinces an acid. Dr. Bruggmans, who has analyzed it with much care, asserts that it has an acid also before putrefaction; but this has been denied by Sir Everard Home*. For a further account of its chemical properties, the reader may consult Dr. Pearson's elaborate paper on this subject in the Philosophocal Transactions+. In the process of the natural cure of an aposteme, we find that the stage of granulation, and consequently of incarnation, immediately succeeds that of ulceration or the removal of the dead matter. "The vessels ", says Mr. Hunter, forming themselves into a certain structure which fits them for secreting pus, it is so ordered that the same structure also fits them for producing granulations; and thus these two processes are concomitant effects of the same cause, which cause is a peculiar organization superadded to the vessels of the part."+ The idea of a change of organization is hypothetical, * Dissertation on the Properties of Pus, p. 20. † Vol. 1809, p. 313. See also a further description under Marasmus Phthisis in the sequel of the present volume. On Inflammation.--Of Pus, p.433. Granulation and incarna tion. Change of organization hypothetical, but perhaps correct. GEN. I. SPEC. I. Apostema commune. Common aposteme. Use of granulation. How it takes place, consist of, J. Hunter. but ingenious, and perhaps correct. Change of action and change of effect we know; but at the rest we can at present only give a guess, and must leave it to future times to ascertain. The obvious design of granulation or incarnation, as it is often called, is that of repairing the loss the parts have sustained by the injury done: it is that of producing new flesh. Granulation, like vegetation, takes place from the centre below, in a direction upwards towards the skin; and hence exactly contrary to the course of ulceration, which always begins in the superior part of an abscess. The process commonly succeeds best upon exposure to the air, or at least after an opening externally; though there are instances of its having occurred where and what the there has been no exposure whatever. The granulating pullulations pullulations, according to Mr. Hunter's explanation, according to consist of exudations of coagulating lymph from the vessels. He conceives it probable not only that the old vessels extend into these pullulations and become elongated, but that new vessels also form in them, and, like the old, still continue to secrete pus. The granulations, as they become formed, mutually and readily unite; inosculation or the attraction of cohesion is established be tween them; and their vessels thus joined are transformed from secreting into circulating tubes. Immediately upon their formation, cicatrization seems to be in view. The parts which had receded, in consequence of a breach being made into them, begin now from their natural elasticity, and probably from muscular contraction, to be brought nearer together by the new-created substance; and the contraction of the sore proves a sign that cicatrization is speedily about to follow. This contraction takes place in every point, but principally from edge to edge, which brings the circumference of the sore towards the centre: so that the exposed surface becomes smaller and smaller, even before there is any formation of a new skin. Two parts of the re storative There are two parts, at least, of this wonderful economy that still demand explanation. The first is the real use of the pus after it is secreted: and the second, the means already been sufficiently shown. "But I am apt to be GEN. I. SPEC. I. Apostema commune. Common aposteme. process that still require explanation. The use of lieve", says Mr. Hunter, "that we are not yet well, the pus: or perhaps not at all, acquainted with its use, for it is common to all sores; takes place in the most perfect degree in those sores which may be said to be the most healthy, and especially in those where the constitution is most healthy."* It forms indeed, an exit to foreign bodies: is supposed by many to carry off humours from the constitution, or convert general into local complaints; and by others to act as a preventive of numerous disYet all these services, even admitting them to exist, are but secondary, and the final intention still remains to be accounted for. and how the becomes fitted for dead matter absorption. In like manner, since the dead matter of an aposteme does not constitute the pus that is found in it, and hence can only be carried off by absorption, we have yet also to learn by what means it becomes prepared for an entrance into the delicate mouths of the absorbent vessels. There is no small difficulty in conceiving how these very minute mouths can apply themselves with sufficient activity to the various tough and hard substances they have to remove, as tendon and bone, when in close contact with them; but, as soon as the dead part becomes separated from the living, they are often no longer in close con tact with them, except at the base, where there is little or no absorption at all; and in many cases, as in boils, These difficarbuncles, and other imperfectly suppurating tumours, possessing cores or tenacious sloughs, are at a considerable distance from them, with the entire body of the contained pus placed intermediately in the hollow. In the last case it seems impossible for them to act culties ex plained. GEN. I. SPEC. I. Apostema commune. Common aposteme. Pus pos vent power: yet not of the kind except through the medium of the pus; in reality except through a solvent power possessed by the pus and exercised upon the matter to be removed. And if such be the nature of the action in this case, it is doubtless the nature of the action in all other cases; and hence we sesses a sol- arrive at one immediate and direct use of pus, which is, that of becoming a solvent of the dead animal matter that requires to be carried off: not, indeed, by converting the whole substance at once into a solid mass, and still less into a fluid mass of its own nature, as supposed by Sir one import- John Pringle, but only the surface of the substance to which it is applied: and which hereby is rendered fit for absorption, carried forward to the mouths of the imbibing vessels, and absorbed accordingly. And as the same power is exerted in succession upon every fresh surface of the dead matter that becomes exposed to its action, the whole is at length carried away, and a cavity produced where before was solid substance. supposed formerly: and hence, ant use of this fluid. How far Hewson's view correct. How far view erro- Hunter's appeal to That pus first kills and then dissolves the organized matter of an abscess was, as we have already seen, the opinion of Mr. Hewson. In the first part of this opinion he was completely mistaken; for, as we have already observed, the organized matter is dead before the process of suppuration even commences; in the second, he seems to a certain extent to have been correct, though he still erred in supposing the dead substance to be melted down into its own nature, and was unacquainted with the important process of its absorption. But in advancing his own full and more elaborate hypothesis against the mistake of Mr. Hewson, Mr. Hunter ran into the opposite extreme; and contended that pus is not designed to be a solvent at all, and that animal substances are decomposed in it with very great difficulty: thus leaving us totally at a loss to account for its use; and equally so to explain the manner in which the mouths of the absorbents of an abscess can operate upon or even, in many instances, get at the material they are to remove. Mr. Hunter, however, with the candour that so pecuexperiments. liarly belonged to him, made this question a subject of |