256 



THE MICROSCOPIST. 



catarrh of the skin, having its origin in hypersemia of the 

 papillary layer (Fig. 206). 



FIG. 206. 



Vertical section through the skin after chronic eczema, a. Horny layer, b. Mucous 

 layer of epidermis, c. Pigmented stratum of cylindrical cells, d. Papillary layer, e. 

 Cutis pervaded by stripes of pigmeat. After RINDFLEISCH. 



The stratum of Malpighi in the skin is analogous to 

 the softer epithelium of mucous surfaces, hut catarrhal 

 processes in the skin are modified by the horny layer, 

 which is first destroyed in the instances referred to, and 

 then the multiplying epithelium cast off. 



Fibrinous exudation consists of fluid from the hyperae- 

 iriic vessels, which coagulates into fibres between whose 

 meshes serum is confined. Pus-corpuscles are generally 

 mixed with the exudation, constituting a fibrino-purulent 

 exudation. These occur principally on the surface of serous 

 membranes. The coagulated fibrin either glues the two 

 surfaces of the membrane together, or forms a slightly 

 adherent layer of membrane, in which the exuded cells 

 develop a true connective tissue (Fig. 207). 



The false membranes which occur in pleuritis or peri- 

 carditis, generally of rheumatic origin, are examples of 



