316 



HISTOLOGY OF THE MORBID PROCESSES. 



FIG. 279. 



Fibrinous leptomeningitis : a, cerebral cortex ; ft, serum, with detritus, separating the brain 

 from the pia mater ; c, bloodvessel of the pia mater, the walls of which are infiltrated 

 with emigrating leucocytes ; d, fibrinous exudate ; e, smaller vessel of the pia. 



fibrin. Fibrin is also frequently deposited, or rather formed, upon 

 the pleural surfaces ; but agglutination of the opposed surfaces, 

 with the formation of adhesions, is prevented by the fluid that 

 keeps them apart. Another common site for serous inflammations 

 is the skin, slight burns causing a serous exudation under or within 

 the epidermis, the horny layer of which is raised to form the cover- 

 ing of a blister. Serous inflammations may also affect other por- 

 tions of the body (Fig. 280). 



Under the microscope a few leucocytes and blood-corpuscles can 

 be detected in the serous exudate. Some of the leucocytes may be 

 infiltrated with fat-globules, which they have appropriated from the 

 debris of degenerated cells. These drops of fat may be so numer- 

 ous as to obscure the nucleus and completely fill the cytoplasm, dis- 

 tending the cell to fully twice its normal size. These cells have 

 received the name "compound granule-cells" (Fig. 195). When 

 the inflammation affects a serous surface detached and swollen 

 endothelial cells may also be present in the fluid. 



5. Catarrhal inflammations are those which affect mucous mem- 

 branes, with the production of a fluid exudate appearing upon their 



