2y(i 



Inflammation. 



which are occupied by leucocytes, desquamated epitheUum and 

 serum. By the cohesion of the fibrin, originally separated in the 

 form of fine fibrils, thick homogeneous trabecula are sometimes pro- 

 duced (hyaline fibrin). 



Fibrin may be well demonstrated in 

 microscopic sections by Weigert's double 

 staining method, the fibrin taking an in- 

 tense blue tint, and the rest of the tissue 

 a red contrast color. 



Inflammations of mucous mem- 

 branes, in which in addition to the 

 formation of a fibrinous exudate there 

 takes place a coagulation necrosis of 

 the tissue of the mucous membrane, 

 are spoken of as diphtheritic inflam- 

 inations {5i<t>eipa, membrane). The 

 coagulation-necrotic mass is here 

 seen as a grayish-yellow to straw- 

 colored or dirty gray, soft and pulta- 

 ceous or drier, very opaque and usu- 

 ally fragmented material. which 

 stands out sharply from the slightly 

 transparent normal tissues as a 

 thicker, somewhat swollen, promi- 

 nent part. Here the deeper parts of 

 the mucous membrane are permeated 

 with the exudate, and the substance 

 cannot be as readily separated from 

 the underlying tissue as the ordinary 

 croupous exudate, the mucous mem- 

 brane being torn when attempts are 

 made to scrape it away. 



This combined inflammation and 

 p. g^ necrosis in its typical form is met in 



Croupous membrane in trachea the digestive tract of swine afifccted 

 (opened) of cow. ^^..^j^ ^^^^.^^ ^\?igix^, and is oftcn Seen 



in calves in the pharynx and larynx following traumatic 

 infectious influences, in birds in the mucous membranes of 

 the head, and in horses in the larynx and trachea after drenching. 

 There are a number of microorganisms (bacillus necrophorus, 

 suipestifer, streptococci and others) which are capable of inducing 

 coagulation necrosis of tissues and giving rise to the anatomical 

 picture of a diphtheroid inflammation.^ 



