The cutis may lose its consistence in several manners. When considerable quantities of serum are collected in the subcuticular cellular tissue, the cutis becomes mechanically dis tended and remarkably soft ; and sometimes is only represented by a thin friable tissue, which breaks down with the least pressure. It may gradually lose its fibrous structure and degenerate into a tissue analogous to that usually found beneath it.
Softening also occurs as a sequel of acute active local congestion.
The appendages of the skin, the nails, hairs, and, in the lower animals, horns, undergo softening to a certain extent in diseases of' long standing, attended with great emaciation ; and softening of the cornea with ulceration is a common symptom of' starvation.
Induration of mucous n2embranes, is gene rally caused by long continued sub-acute in flammatory action ; the sub-basement cellular tissue is generally affected, and thickening of the whole structure, with hypertrophy of the papillm, where they exist, is found at the same time. Induration with hypertrophy is consequent upon chronic (13 sentery, and upon chronic inflammation of the bladder. Ulcer ation of mucous membrane is generally ac companied by surrounding thickening and induration, and this last is frequent in the gall-bladder, gall-ducts, uterus, and urethra. Induration of mucous membranes is generally accompanied by contraction of their caliber or surface, — from the consolidation and subse quent contraction of lymph effused into the cellular structure. Fatal stricture of the in testines is produced in this manner, and so are urethral strictures. Ulceration of the stomach when healed, is followed by contrac tion of the cicatrix ; and when the ulcer has extended into the duodenum from the stomach, pyloric constriction of the severest kind occurs. The colour of indurated mucous membrane is generally paler than natural: the opposite-may occur, and the degree of density varies from a slight increase to a bony hardness.
An indurated and thickened state of the mem branes of the brain, pericardium, and pleura, are found after long continued chronic in flammation, either of the membranes them selves, or of the parenchyrnatous structures in their vicinity. Effusion of lymph behind serous membranes always tends to their be coming harder and thicker than natural; after a while the lymph becomes organised and contracts, and produces a puckering and ir regularity of the membranes. We find thick
ening and induration of the pleura over large tuberculous cavities, the peritoneum covering the liver, and intestinal canal, and in the sacs of old hernim. Constriction of any part of the intestinal canal, and also of the pylorus, may be produced by sub-peritoneal effusion of 13 mph.
Softening of the liver usually occurs in a manner not to be appreciated by the eye, being simply easily broken down under the finger ; occasionally, however, the liver looks as if it had been macerated for a great length of dine in a dark fluid, its texture has completely lost its cohesion, and has become in certain spots quite diffluent. Livers in a state of softening may retain their ordinary colour, or it may be increased, and even decreased, in an extraor dinary manner ; for, sometimes, no traces of blood cau be found, except in the larger venous trunks, and the tissue of' the liver is pale and light drab in colour. Softening of the liver is found frequently on the anterior and convex surface, as a product of inflammation ; partial and curable softening has been noticed to ac company inflammation of the right lung; and, finally, the consistence of the liver is much influenced by the abnormal deposition of fat, which sometimes occurs in the ultimate cells of the organ.
Induration of the liver is generally produced by the deposition of lymph, its subsequent contraction and its compressing influence upon the lobules. This effusion is the con sequence of adhesive inflammation in the are olar tissue about the twigs of the portal vein, serum and coagulable lymph are poured out, the first is absorbed, and the latter consolidated, and uftimately converted into dense fibrous tissue, which divides the lobular structure of the liver into well defined masses, gives great density and toughness to the organ, by com pressing the small twigs of the portal vein, and the small bile ducts, thus impeding the flovr of blood and the escape of bile, and causing the usual yellow tint which accompanies this disease.