SEROUS AND SYNOVIAL MEMBRANES. 



537 



a slight effusion, which is followed by an ad- 

 hesion of its visceral and parietal layers ; an 

 effect which is usually attributed to an " irri- 

 tation " of the part by the disease. And as 

 this process generally precedes any similar 

 extension of ulceration to these membranes, 

 it has the salutary result of sealing up their in- 

 terior, and thus of preventing what would 

 otherwise be a serious or even fatal effusion 

 into their cavity. Their destruction by the 

 communication of an ulcerative process in 

 their immediate proximity may be called by 

 the same name ; but it often more resembles 

 sloughing in the rapidity of its course, and in 

 the imperfect absorption of the broken down 

 textures. So also where softening of these 

 tissues happens, it almost invariably depends 

 upon an action which primarily affects the 

 subjacent viscera, and gradually implicates 

 their serous covering. 



Tubercle. The deposit of this morbid 

 product in the cavity of a serous membrane 

 constitutes but a part of the general tuber- 

 cular cachexia; and in the majority of in- 

 stances, it only occurs after the disease has 

 been localised in some other organ ; often, 

 indeed, after it has already implicated the 

 respiratory apparatus. And even in those 

 cases in which its symptoms precede other 

 manifestations of the disease, it appears ex- 

 tremely probable that the lymphatic glands 

 of the immediate neighbourhood have been 

 tbe original seat of the deposit, and that from 

 thence it has, as it were, extended to the par- 

 ticular serous membrane. 



Occasionally, the tubercular matter is de- 

 posited in and amongst the effused products 

 of inflammation, so that the two processes 

 appear to merge into each other, with a 

 similar mingling of their products. This 

 occurrence of tubercle in connection with 

 inflammatory exsudation has been minutely 

 described by Rokitansky, who considers 

 that a complete metamorphosis of the latter 

 substance into the former does, in some 

 instances, obtain. But from the difficulty of 

 procuring direct evidence upon this point, 

 z. e. of examining different portions of the 

 same effusion at different periods of its dura- 

 tion, one may be allowed to doubt whether 

 such a transmutation, or even a substitution, 

 is really effected. 



Generally speaking, the coexisting inflam- 

 mation plays a more subordinate part. 

 Where the tubercular matter is thus compa- 

 ratively uncomplicated, it occurs in the form 

 of greyish semi-transparent granulations, of 

 about the size of a millet-seed, or rather 

 larger. The situation of these is usually on 

 the inner surface of the membrane, which 

 they render irregular by their presence, so 

 that on removing a tubercle (which is easily 

 peeled off from the subjacent texture), a 

 depression of a size which corresponds to it 

 is exposed, in which the serous membrane 

 has lost its smooth and shining character, 

 and has become dull and somewhat opaque. 

 Besides this, which is the ordinary form of 

 tubercle in these textures, other and smaller 



varieties often occur : and where a large 

 quantity of the deposit is present, more or 

 less exsudation unites the whole into a 

 layer ; in which, however, the granularity of 

 their developement can till be discerned. 

 Usually, a certain amount of serous fluid is 

 also present, the quantity of which has some 

 relation to the extent of the disease. In the 

 peritoneum, however, its quantity is for the 

 most part insignificant ; and the cavity of the 

 serous membrane is completely filled by a 

 thick and solid, yet granular mass of tuber- 

 cle, by which the viscera and abdominal 

 parieties are completely matted together. 

 Sometimes, but rarely, the texture of the 

 serous membrane itself, or the subserous 

 areolar tissue, becomes the seat of the de- 

 posit ; in these cases its quantity is small. 

 The after-changes of tubercle in these tissues 

 may lead to suppuration and ulceration, or 

 to a slow absorption of the organic constitu- 

 ents of the mass, and a cretification of the 

 remainder ; but in the greater number of 

 cases, the patient dies of the general disease 

 without either of these events having hap- 

 pened. 



Cancer of these tissues is comparatively 

 rare : and of those instances which do occur, 

 many are scarcely affections of the serous 

 membranes themselves, but ought rather to 

 be considered as secondary, and dependent 

 on a mere local proximity. Thus, a neigh- 

 bouring cancerous tumour, by the progress of 

 its growth, comes into contact with a serous 

 membrane, and, as its size increases, gradually 

 implicates this structure in its own diseased 

 mass. Sometimes they are primarily at- 

 tacked ; yet even here, other organs gene- 

 rally suffer at the same time, and either com- 

 plicate or mask the local disease. 



The carcinomatous deposits themselves 

 offer few special peculiarities of appearance. 

 The harder or scirrhous forms are seldom 

 seen ; the softer varieties, viz. the gelatini- 

 form or areolar, the medullary, and the me- 

 lanotic, being those to which they are most 

 liable. For a description of these the reader 

 is referred to the article ADVENTITIOUS 

 PRODUCTS. 



Ossification of the serous membranes is 

 also infrequent. Like the same process else- 

 where, the deposit of bony matter never 

 occurs alone, but is a very slow change, 

 which appears to require the existence of a 

 previous tissue. Hence, it is limited to two 

 forms, neither of which primarily affect the 

 cell-growing membrane. In the first, the 

 fibrinous exsudation of a preceding inflam- 

 mation is gradually transformed into ossific 

 matter. In this case, the shape of the de- 

 posit is rough and irregular, and sometimes 

 it forms a kind of nucleus, which occupies 

 the centre of the tough fibrous mass. Its 

 appearances sometimes approximate to those 

 of the cretification before alluded to, as pos- 

 sibly do the several processes which form 

 these substances. In the second variety, 

 the subserous and neighbouring areolar tissue 

 is occupied by the deposit ; but here also 



