Change Of Texture Which Mucous Membrane Undergoes when pre-ternaturally exposed to atmospheric air, and when long subjected to distension. - a. The mucous membrane of prolapsed and everted organs is liable to the former kind of change. At first an acute inflammation attacks it and occasionally rises to considerable severity, but afterwards it becomes chronic, and at length terminates in induration. Such membranes become dark red and swollen; their secretion soon increases in quantity, and then they produce a puriform moisture: they may even clothe themselves with a plastic exudation, while underneath they appear raw and excoriated. At length the inflammation moderates, the secretion just mentioned ceases, and the redness diminishes, but the membrane remains thickened, and its texture more compact than natural; it is covered with a thick closely-adherent layer of epithelium; and hence appears dry on its surface, smooth, and glistening; its internal texture resembles that of tendon; and it acquires something of the appearance of the corium, or of a regenerated, or cicatrix, tissue.

b. The second change of texture affects the inner coat of the excretory ducts and reservoirs of glands, and of other hollow organs which are lined with mucous membrane: and the condition under which it occurs is that of some contraction or closure of the orifice, in consequence of which the secretion of the gland, or of the mucous membrane itself, accumulates, and gradually distends the cavity beyond its normal dimensions. It is observed in the gall-bladder, in the Fallopian tubes, and even in the uterus, in the excretory apparatus of the kidneys, and in the appendix vermiformis of the caecum. This change of texture consists in a slow atrophy of the mucous membrane, and gradual condensation of the submucous cellular tissue to a serous layer, which at last takes the place of the mucous membrane. The tissue being changed, of course the secretion also is gradually altered; and instead of mucus a fluid like synovia, and afterwards a thin serum, are secreted. This condition bears generally the name of dropsy of the respective organs, - dropsy of the gall-bladder, of the Fallopian tubes, of the uterus, etc, - dropsy of the excretory ducts of glands. The membrane which usurps the place of the mucous structure is thenceforward subject to the diseases of serous membranes in general; and some of them are remarkable as not occurring to normal mucous membrane, or to submucous cellular tissue; such for instance as ossification.