Such is the natural progress of an abscess; but it has been proposed, that it ought not to be allowed to follow this, but ought to be opened before it bursts spontaneously; and this opening has generally been desired to be pretty large, chiefly perhaps on the principle of allowing a free evacuation of the matter. Where abscesses are seated over cavities into which they may burst[28], instead of opening externally, there can be no doubt of the necessity of making an early evacuation; and, in these cases, we ought to open them before the skin becomes white; or, in other words, before the action reaches the surface; because, if the abscess be seated equally betwixt the skin and the cavity below, we may suppose, that, if it be extending itself in all directions, or toward the cavity[29], in the same proportion as outwardly, that the parts below will become almost irreparably diseased before it can reach the surface, and will give way afterwards[30], even although an opening be made externally. Where, from the confinement of the matter, it seems to be spreading, or diffusing itself, by its gravity, through the cellular substance, or among the muscles, it will likewise be necessary to open the abscess early; but, in this case, the abscess is unhealthy; for, were it otherwise, the matter would be confined by the circle of diseased organic matter thrown out during the inflammatory action, and which is only removed gradually. In this case, the suppurative action has extended itself laterally, and perhaps downward, more quickly than in health, and has not observed the same ratio, with regard to the extension toward the surface; the action, therefore, reaches parts which were not formerly inflamed (by the sympathia consociationis serpens), before the surface gives way; and, therefore, the matter spreads or diffuses itself; for, by the spreading of the action, the confining barrier is removed, and the matter mechanically extends itself. This is an unhealthy abscess, and the action is of the phagedenic nature. Opening the abscess will not always stop this morbid action; but, by removing the matter, it will lessen the chance of diffusion. We must, however, continue the free evacuation, and place the member in a proper posture; because, if the action continue, the matter which still is formed will lodge, and form sinuses. [28] Such as the thorax, trachea, &c. Instances have happened of suffocation being thus produced.