If we consider these adhesions in relation to their frequency in the serous cavities, we see that they exist most frequently in the pleura, existing in nearly half the adult bodies ex amined. After the pleura comes the perito neum, then the pericardium ; those of the tunica vaginalis are less common, but the arachnoid is, of all serous membranes, especially relative to its extent, that where these adhesions are most unfrequent.
The absence of mobility appears singularly to favour this phenomenon : thus in the pleura they most frequently occupy the superior parts, and in the peritoneum most frequently occur between the viscera forming a hernia, and be tween the convex surface of the liver and the diaphragm.
The membranes between which such adhe sions occur, must usually, of course, be in intimate relation, the one with the other during the time when the process is in progress of accomplishment, though now and then the distance is considerable; but they may after wards become separated to great distances : those cellular bands which are so commonly seen in the thorax are evidences of this fact.
Some circumstances tend to demonstrate that these bands in serous structure may at a certain period of their existence be absorbed and disappear, and the secreting surface be reproduced. M. Ribes states that occasi onally we do not find any trace of such bands, nor any adhesion in the peritoneum of persons who have had penetrating wounds of the ab domen. Beclard examined an insane person who had several times stabbed himself in the abdomen. At the points where the more recent of these wounds had been inflicted considerable adhesions were found; beneath the older cicatrices no vestige of adhesion was found. A case of artificial anus occurred in the practice of M. Dupuytren, by which faecal matter passed during twelve days. The pa tient died at the end of seven months. At the examination after death, it was found that the portion of intestine in which the accidental opening had existed, was distant from the ab dominal cicatrix between four and five inches. A very attenuated cellular band extended from the cicatrix to the portion of intestine. Doubt less a short time would have sufficed for the absorption of this band, when the intestine would have .been set at liberty and the serous surface restored.
In the course of lectures which Bichat de livered only a few months before his death, he maintained that adhesion was never pro duced between mucous surfaces, and that con sequently the cavities lined by this tissue were never obliterated. Few statements have given rise to more extensive discussion than this ; few discussions have up to the present moment been attended by less satisfactory results. In his first dictum I believe he was clearly right, in the second as clearly wrong.
Mr. Hunter's opinion was in accordance with that of Bichat : he says, " that in all the outlets of the body called mucous membranes, the order of inflammation differs from that which occurs in cellular membrane, or in cir cumscribed cavities. In these latter adhesive inflammation is immediately admitted to ex clude, if possible, suppuration." In internal canals, where adhesions would in most cases prove hurtful, the parts run immediately into the suppurative inflammation, the adhesive in flammation being in common excluded.* Mucous membranes, when unchanged by disease, are not capable of becoming adherent the one to the other, and the reason of this is simple. 1 have already stated that no per manent adhesion can occur in the living body without the intervention of a new tissue, which at a certain indefinite or undetermined period of its existence becomes organized.
A pseudo-membrane of considerable extent may be thrown out upon an inflamed mucous surface; but this membrane, I apprehend, never becomes organised, and union between mucous surfaces cannot therefore be permanent unless some other agency be called into action. But, as soon as inflammation has destroyed the characters from which these membranes derive their name ; when the mucus, which like an inorganic layer appears to oppose itself so successfully against immediate contact, thereby preventing the organization of the effused mat ter, no longer exists; when the cellular element which forms the basis of this membrane is developed, then adhesion by means of the union of granular surfaces is effected with the greatest facility ; of this we have evidence in most of the mucous canals. It is not rare, for instance, to meet with complete obliteration of the vagina, of the cystic duct, and so on.