The dissolution of the living solids of an animal body into pus, as an essential part of the process of suppuration, and the power of the fluid to continue the dissolution, are opinions which are no longer entertained. If these notions were true, no sore which discharges matter could be exempted from a continual dissolution. Such ideas probably arose from the circumstance of an abscess being a hollow cavity in the solids, and from the supposition that the whole of the original substance of that cavity was now the matter which was found in it. This was a natural way of accounting for the formation of pus by one entirely ignorant of the circulation, and what takes place in an abscess after it is opened. According to the above erroneous principle, abscesses would continue to increase after being opened as fast as before. Upon the principle of the solids being dissolved into pus, was founded the practice of bringing all indurated parts to suppuration if possible, and not making an early opening. This was done for the purpose of giving time for the solids to melt down into pus; but it was apparently forgotten that abscesses formed matter after they were opened, and, therefore, the parts stood the same chance of dissolution into pus as before. Blinded with the idea that the solids entered into the composition of pus, the partisans of this doctrine could never see pus flowing from any internal canal without supposing the existence of an ulcer in the passage. Such sentiments might be forgiven while it was not known that these surfaces could, and generally did, form pus without a breach in the solids, but the continuance of this way of thinking now is nothing short of stupidity. The formation of pints of matter in the cavities of the chest and abdomen, without any breach in the solids, could not be overlooked by the most zealous advocates for the doctrine of dissolution.

The moderns have been still more ridiculous; for, knowing that it was denied that the solids were ever dissolved into pus, and that there was not a single proof of it, they have been busy in producing what to them seemed the best of evidence; they have been putting dead animal matter into abscesses, and finding that it was either wholly or in part dissolved, they therefore attributed the loss to its being turned into pus.

This, however, was putting living and dead animal matter upon the same footing, which is a contradiction in itself, for if the result of this experiment were really what they supposed it to be, the idea of living parts being dissolved into pus must be abandoned, because living and dead animal matter can never be considered in the same light. It might have been remarked, that even extraneous animal matter would lie in abscesses for a considerable time without being dissolved, and that in abscesses arising either from violence or from a species of erysipelatous inflammation, there were often sloughs of the cellular membrane, which sloughs would come away like wet tow, and therefore were not dissolved into pus.

Again, it is observed that in abscesses of tendinous parts, a tendon often mortifies and sloughs away, and that the sores will not heal till such sloughs are detached; hut though this separation is sometimes not completed for several months, yet the sloughs are at last thrown off and not converted into pus.

Pieces of dead bone often lie soaking in matter for many months without being changed into pus, and although bones so circumstanced may lose a considerable deal of their substance, a loss which some might compute to the dissolution of the bone into pus, yet such waste can be accounted for on the principle of absorption. The loss is always upon that surface where the continuity is broken off, and it is a part of the process by which the exfoliation of a dead piece of bone is accomplished.

The formation of pus has been attributed to a kind of fermentation, in which both the solids and fluids are fancied to be concerned. This doctrine is easily refuted by stating what happens in internal canals which naturally secrete mucus, but frequently form pus without any loss of substance, or any previous fermenting process.

It may be asked, likewise, by what power the first particle of pus in an abscess, or on a sore, is formed before there is any particle existing which is capable of dissolving the solids? An abscess may be stationary for months, and at last be absorbed, but what becomes of the fermentation all the while the collection of matter continues stationary?

Extravasated blood has been supposed to be capable of being converted into pus. We find, however, that blood, when extravasated, either from violence or the rupture of a vessel, never of itself becomes pus, nor was pus ever formed in these cases without being preceded by inflammation. Both the blood and the matter are formed together in the same cavity under such circumstances. If the blood had coagulated, it would be found in that state, and if it had not coagulated the pus would be bloody.

Violence done to parts is one of the great exciting causes of suppuration, but simple violence does not always occasion it. The violence must be followed by something that prevents the cure in a more simple way, something that prevents the restoration of the structure and the continuance of the animal functions of the parts. The parts must be kept long enough in that state into which they were put by the viol ence, or, what is somewhat similar to this, the violence must be attended with death of the part, as in many bruises, all mortifications, and all sloughs, in consequence of the application of caustic, which, when the dead parts separate, leave internal surfaces exposed.

As every injury, or effect of outward violence, under the above circumstances, is more or less exposed to the surrounding air, the application of air to internal surfaces has been assigned as a cause of suppuration; but certainly the air has not the least effect upon parts circumstanced as the above, for a stimulus would arise from a wound, were it even contained in a vacuum. In circumscribed abscesses the air cannot possibly get to the parts, so as to have any share in causing them to suppurate.