The forms in which this kind of inflammation occurs are furuncle and anthrax; it occupies the deeper, areolar layer of the corium, and the cellular tissue filling the interspaces of its network. A circumscribed swelling at first presents itself, no larger than a hemp-seed or a pea, which, as it gradually increases in size, becomes remarkable for the (reactionary) inflammation that attends it: for the inflammation forms proportionally a wide halo around the swelling, corresponding with the pain and the marked degree of tension that exist; it reaches also into the deeper structures, and fixes the swelling of the skin to the subcutaneous cellular tissue. Before reaching its highest point of severity, it furnishes a product that is known by the name of a (Pfropf), core or plug. This product has been regarded as sloughy cellular tissue; but, upon more thorough examination it is found to be a product of the inflammation going on in the cellular tissue contained in the meshes of the corium, and to resemble false membrane, - to be, therefore, exudation. It occupies the whole thickness of the corium, and exists there before the swelling is very perceptible: at first, it is closely connected with the surrounding injected tissue, but, as the (reactionary) inflammation around it produces suppuration, it is thrown out. The core has in fact nothing in common with separated sloughy cellular tissue, it is exudation; though it certainly may contain a few fibres of cellular tissue interwoven with it, which have been severed from the rest by the suppuration going on around it. (Gendrin, Ascher-sohn).

In furuncle only one such product is formed; in anthrax there are several of them near together. The reactionary inflammation around and beneath is very considerable, corresponding in degree to the pain and the feeling of tension. If before the commencement of suppuration, and consequently before the loosening of the cores, an incision be made into an anthrax, a uniformly red, spongy, or reticular tissue is exposed, the meshes of which are filled with cores. At a later period, when the cores are loosening from the inflamed tissue, and suppuration is just coming on, each core is found surrounded by a substance like jelly. When, at length, suppuration is established, the cores become completely separated, and, by the destruction of the meshes of the network, cavities of different sizes are formed, in which they freely swim.

Instead of leading to the production of matter, and suppurative destruction of the tissues, the process sometimes terminates in another way; for, under a combination of excessive local tension, and unfavorable general circumstances, viz., in the condition of the individual, and in external influences, mortification takes place, especially in the skin covering the carbuncle.

Furuncle very rarely terminates in induration; it might, when such is the case, be confounded with several other circumscribed inflammations of the skin.

There are various other inflammations of the skin allied to furuncle, but differing from it: some are primary, others secondary (or, as they are called, metastatic, critical). Some are parenchymatous, others proceed from particular parts of the structure of the skin, especially from the sebaceous glands. They may terminate in suppuration or in induration.