These different conditions will be best under stood by tracing a rupture through each of them in succession.
A person may be suspected to have a reduci ble hernia when, after the application of some force calculated violently to compress all the viscera of the abdomen, an indolent tumour appears proceeding from some of those places where the walls of the abdomen are known to be weakest and least resisting. And the sus picion is increased if the tumour is elastic, if it sounds clearly on gentle percussion, and becomes suddenly puffed up and swelled, as if by air blown into it, when the patient coughs, sneezes, or performs any of those actions which forcibly agitate the abdominal parietes. The reducible hernia becomes smaller or perhaps disappears altogether when the patient lies down : it appears of its full size when he stands erect ; if neglected, it has a constant tendency to increase, which it does sometimes by de grees, slowly and almost imperceptibly, but more frequently by sudden additions to its bulk, which are formed by new protrusions. In this form of the disease the qualities of the viscus engaged within the sac, as to form, size, and structure, may be considered as unchanged : within the abdomen, however, the fold of mesentery which supports the protruded intes tine is constantly more elongated than it natu rally should be, and likewise thicker and more loaded with fat. It is also marked with dilated and tortuous veins.
Although thus displaced, the viscus is still capable of performing its part in the function of digestion, and as long as the contents of the bowel pass fairly and uninterruptedly through it, there can be little or no danger ; but it is not difficult to conceive how a gut so circum stanced may occasion great inconvenience. The peristaltic motion must be more or less impaired ; the passage of the contents may be delayed, and hence will arise nausea, colicky pains, eructations, and those other dyspeptic symptoms from which even the most favoured patients do not escape. These irregularities again can soarcely exist for any length of time without producing some inflammation, and thence it follows that it is rare to meet with an old hernia in which adhesions have not formed either between the intestine and the sac, or between the convolutions of the protruded viscera, circumstances that must render it im possible to replace the hernia, or supposing it replaced by force, will be likely to occasion incarcerations within the cavity of the abdomen itself. These adhesions, as discovered either
during operation, or by dissection after death, are of different degrees of closeness, firmness, and tenacity, and have been arranged under three classes, the gelatinous, the membranous, and the fleshy.
"The gelatinous adhesion, a very general consequence of the adhesive inflammation which attacks membranous parts placed in mutual contact, is only formed by a certain quantity of coagulable lymph, effused from the surface of the inflamed parts, which coagulating assumes sometimes the appearance of a vesi cular reddish substance stained with blood, sometimes of threads or whitish membranes easily separable from the parts between which they are interposed and which they unite to gether, without any abrasion or laceration being produced by the separation, on the surface of the parts agglutinated together." This kind of adhesion being the result of recent inflam mation can rarely be met with in operations performed for the relief of strangulated hernia, for the condition of a viscus so engaged is that in which such an effusion would be unlikely, if not impossible. Its vessels are loaded and congested with venous blood : there is effusion of serum to a greater or less quantity, as is seen in every instance of obstructed venous circu lation ; and if there is recent lymph, it must be owing to the fortuitous circumstance of the viscus having been inflamed immediately before it became strangulated. In a vast number of cases operated on, I have seen but one instance ofthe existence of this soft adhesion, and in that the hernia was not strangulated : it was a case (such as is related by Pott) of inflammation affecting the intestines generally, in which those within the hernial sac, of course, participated.