14 INFLAMMATION. 



where generally no fibrine is formed, but mucus, which does 

 not exist in the blood. An inflamed mucous membrane pro- 

 duces large masses of epithelium in a short time; they are 

 merely products of the membrane, which is not infiltrated with 

 epithelium or mucus coming from the blood, but the peculiar 

 product of the membrane, and is conveyed to the surface by 

 means of the fluid transuding from the blood. In the same 

 manner, fibrine, instead of being a real exudate from the 

 vessels, is a local product of the tissues on and in which it 

 is found, and is conveyed to the surface, as in pleuritis, in the 

 same way as the mucus of the mucous membrane. We can 

 thus explain that the fibrinous condition of the blood observed 

 in inflammations is a result of the absorption of the increased 

 quantity of fibrine produced by the local metamorphosis of 

 transuded serum. 



We may conclude that the effect of inflammation on all living 

 tissues is a modification of the action of individual cells, result- 

 ing from some alteration in the properties of the walls of the 

 capillaries nearest to the seat of irritation or injury. Most of 

 these modifications are accompanied by transudation of liquor 

 sanguinis — exudative inflammations ; whilst in others, and these 

 are the most destructive, the process is limited to textural 

 changes in the substance of the part — parenchymatous inflam- 

 mation. The latter may, however, in some instances be 

 changed into the former, by increasing the stimulus, or by 

 elevating the vitality of the part ; for, as already observed, 

 the first change noticeable in a non-vascular structure when 

 irritated is similar to that seen in the same structure when 

 removed from the influences of vital action, i.e., excised, and that 

 those processes, peculiar to the inflammatory state, are the natural 

 changes occurring in an injured living structure. Now, if the 

 living structure be much debilitated by any cause previous to 

 the occurrence of the irritation, the natural response will be 

 feeble, delayed, or the part may even die witliout presenting any 

 si^ns of exudative reaction. 



CAUSES OF INFLAMMATION. 



It will be sufficient here merely to notice the remote causes 

 of inflammation. These may be divided into predisposing 



