Fibrinous I n/Janinuitioiis. 275 



may predominate and flakes of fibrin be found floating in it, in a 

 state of fine division (sero-fibrinous exudation). On the mucous 

 membranes also the fibrin may be encountered as membranous lay- 

 ers, which may be pulled ofif in sticky shreds, and which sometimes 

 form distinct casts of the canal ; these are spoken of usually as 

 croupous exudates (according- to Roth tlie word croupous has a 

 Scottish origin). Croupous membranes may be tough or soft and 

 grumous, depending upon the proportionate number of cells present 



■% 





V 



Fig. 53. 



Enteritis membranacea of cat (section). To tlie left tlie pseiirlomembrane cover- 

 ing the intestinal villi, wliicli are the seat of cellular infiltration and des- 

 (inamation ; to the right the muscular layers and the serosa with its adipose 

 tissue. 



and the existence of some degree of degeneration ; they vary from 

 one-half to ten millimeters in thickness ; when separated in the form 

 of tubes they are full of the contents of the mucous canal, as the 

 intestine, in which they develop ; in other instances, as in the lungs, 

 they form solid coagula. Under the microscope, at the beginning 

 of fibrin separation the fibrin threads can often be seen arranged in 

 a stellate, tuft-like manner about the cells which give origin to the 

 fibrin ferment (Hauser) ; sometimes the fibrillar material is depos- 

 ited in parallel layers or is formed in a reticulum, the meshes of 



