INFLAMMATION, 305 



cellular substance of the adjacent connective tissue, it is the 

 vital centre for both. In the j^eculiar structure of the great 

 omentum we have an opportunity of convincing ourselves of this 

 twofold significance of the serous cpithelia. Wc know that the 

 fully developed omentum is in its finer texture a network, whose 

 trabeculcTe are made up of sinuous connective-tissue fibres. It is 

 only the larger trabecuhie which are traversed by an axial blood- 

 vessel. The smaller and smallest ones are simply cylindrical 

 bundles of connective-tissue fibres which contain neither vessels 

 nor cells in their interior. Where then, may we ask, are the 

 corpuscular elements of this connecti\e substance? We must 

 either admit that w^e have here a connective substance destitute of 

 cells, or we must assume that the nuclei of the superjacent 

 epithelia perform the function of coniiective-tissue corpuscles as 

 welL The latter is undoubtedly the more correct view. For if 

 we detach the epithelial layer by the aid of dilute acetic acid and 

 a moderate amount of mechanical force, we often find that the 

 nucleated masses of protoplasm remain adherent to the connective 

 tissue, while the plates are set free without their nuclei. The 

 same phenomenon, as we shall see forthwith, occurs at the out- 

 set of acute inflammation. Moreover, the products of morbid 

 growth originate from these cells also ; so that the pathological 

 histology of the serous membranes is one long chain of evidence 

 in favour of the view that their epithelia are at the same time 

 the outermost cells of the connective tissue. 



As regards the connective-tissue stratum of the serous mem- 

 branes, I need only say that it is nearly always of extraordinary 

 thinness, and that, particularly in the visceral laminae of those 

 organs which are subject to considerable variations in bulk, it 

 contains a rich network of fine elastic fibres. These fibres are 

 very welcome to the anatomist as a guide to the extent and 

 limits of the serous membrane in transverse sections. 



A. Inflammation. 



§ 268. We will concern ourselves first of all with the struc- 

 tural changes to which an inflammatory irritant gives rise on the 

 surface of a serous membrane.* 



* In the following sections I sliall often avail myself of the admirable 



20 



