The membranous and fleshy adhesions are the results of former attacks of inflammation, and are exactly similar to those attachments so frequently met with between serous surfaces in other situations. When the opposed surfaces lie motionless and undisturbed, their connexion is firm and fleshy, and hence this kind of adhe sion is seen at the neck of the sac, between the omentum and the sac, and occasionally between the intestine and the testicle in congenital hernia; whilst between the convolutions of the intestine itself, or between it and the sac, any union that exists is more generally loose and membranous.
Besides adhesion, there are many other causes that may render a hernia irreducible, one of the most prominent of which is the patient's neglect in leaving the hernia down, and the alterations in shape and structure that thence ensue. In such ease, the parts within the tumour, as the mesentery and omentum, have room to increase, whilst at the mouth of the sae they remain constricted and of their natural though condensed and solidified in structure. This happens particularly with the omentum, which becomes hard, very dense, and compact, and not unfrcquently resembles a fibrous structure covered by a fine smooth membrane, and then there is within the sac a tumour actually much larger than the aperture it would have to pass, and through which no force could be capable of pushing it.
It may happen that the part of the omentum which is below the stricture shall remain loose and expanded, and enjoy its natural structure, whilst that which is lodged within the neck of the sac is compressed and hardened, in which case the hernia will probably prove irreducible.
It sometimes happens that scirrhus of the intestine renders a hernia irreducible. Such a malignant alteration of structure is by no means frequent in the intestinal tube—certainly far less so than in the omentum, but the possibility of the occurrence is proved by a case under my own immediate superintendence. The patient had a large hernia which he had been able occasionally to reduce, but which was usually left down. On a sudden lie was attacked with symptoms of strangulation, small quick pulse, tenderness of the abdomen, acute pain in the tumour, constipation, general low fever and fceeal vomiting. The operation was performed, and the cause of the symptoms found not to have been in the situation of the neck of the sae, which was more than commonly open and free, but in a scirrhus of one of the lesser intestines.*
The form of hernia already noticed as being apparently devoid of a sac has been mentioned by Pout as one peculiarly difficult of reduc tion. "They have consisted of the ccecum with its appendieula and a portion of the colon. Nor, continues this distinguished surgeon," will the size, disposition, and irregular figure of this part of the intestinal canal appear upon due consideration a very improbable cause of the difficulty or impossibility of reduction by the hand only." The last circumstance to be considered as rendering a rupture irreducible is the absolute size of the tumour and the quantity of viscera it contains. It is amazing to what extent the contents of the abdomen may be protruded from it, and the patient nevertheless enjoy a state of health that might be called good, so far as the annoyance of such a tumour could warrant the expression. Every surgeon must have heard of hernia3 in which all the loose intestines were protruded, and in fact every thing that could with any degree of probability be supposed to have been capable of being pushed from the cavity of the abdomen. I have seen and dissected a case of this descrip tion in which the tumour during life reached to within two inches of the knee, and obliged the unfortunate subject of it (who was a lamp lighter) to wear a petticoat instead of breeches. Similar instances are not very unfrequent, and it is obvious that an attempt at reduction here would be injudicious even if it was practicable. It is the nature of all hollow structures in the body, whether cavities or vessels, to accommo date their size and capacity to the quantity of their contents, and the cavity of the abdomen will, under such circumstances, become so con tracted as to be either incapable of immediately receiving the protruded viscera again, or else the sudden distension will excite peritoneal inflammation—an evil greater than the existence of the hernia. These latter, however, cannot be regarded as permanently irreducible, for Arnaud, Le Dran, and Iley have succeeded in gradually restoring them by means of a bandage shaped like a bag, which being laced in front admitted of being tightened still as the tumour diminished.