80 SEROUS MEMBRANES.
ering their respective organs. Thus the large ligaments, quite distant from the womb in the ordinary state, serve it as a serous membrane during gestation; the distended intestine borrows from the mesentery a covering which quits it when it contracts; the epiploon, as M. Chaussier has well observed, is successively a floating membrane in the lower belly, and a tunic of the stomach. Often the peritoneal envelope of the bladder abandons it almost entirely; has not the herniary sack of those enormous displacements of the gastric viscera, primarily served to line the parietes of the abdomen, etc.? Now it is evident, since the different organs can exist separately from their serous membranes, that there is no connexion between their reciprocal organization. 2. It is always a loose tissue, easily distended in all directions, which serves as a means of union, and never a sanguineous vascular system, as in most other adhesions. 3. The disease of an organ is not the necessary consequence of that of its serous membrane, and the contrary; the organ is often affected without the membrane's being diseased.
For example, in the operation for hydrocele, the testicle remains almost constantly untouched, in the midst of the inflammation of its tunica vaginalis; the inflammation of the mucous membrane of the intestines is not the effect of that of their peritoneal covering, and reciprocally in the different acute catarrhal affections of the organs having a mucous membrane within and a serous membrane without, we do not see the latter inflamed, etc. In a word, the dis-
