Pathogenesis. Anatomical Changes. 575 



Pathogenesis Under the influence of the cause of tlie in- 

 flammation the blood vessels of the peritoneum dilate and the 

 endothelial cells are shed at places and there is an immediate 

 escape of serum and red blood corpuscles into the peritoneum. 

 Owing to the richness of the peritoneum in nerves the pain due 

 to the inflammation is continuous and severe and is increased 

 by pressure. As the surface presented by the peritoneum to the 



n^.^^^/.'^f/ n'^'l'-''^ ""'"'^ ^^''''^ P^"^^^^^^*^ i« ^^^^T laro-e, these 

 pass into the blood m large quantities from the very outset and 

 produce general disturbances, the extent depending upon the 

 area involved m the inflammatorv process 



r...}\''' addition to the cause "of the inflammation bacteria 

 products are poured into the peritoneum in large quantities, as 

 IS the case m extensive rupture of an organ, absorption of the 

 toxin may cause death before peritonitis has had time fully to 

 develop. Acute inflammation decreases peristalsis and later 

 suppresses it entirely. This is due to the serous infiltration of 

 the muscular tissue and still more to reflex action 



Tavel and Lanz go so far as to state that bacteria produce no effeS save in «n 



, Anatomical Changes. In the early stages the peritoneum 



IdJwW^tT '"''%' f'^^ f'^'^ 'f^ opaque, ^and is ^f requen ly 

 studded with punctiform heinorrhages. Within the next twenty- 

 four hours there form thin filmy fibrinous membranes which aie 

 T^S. ^'^^'^'f. /1^^«^ '''^y sn1^«equently measure several ml! 

 hmeters m thickness, and while still remaining soft and 



rethe"; T^^^er^i^' ^PP^^^^ '"^"'^ '^ '''' peritoneum to- 

 gether, ihere is a simultaneous accumulation in the 

 peritoneum of a turbid serous fluid containing flocculi 

 of fibrin. In the horse there maybe as much as forty 



much a^s 100 liters. In other cases the exudate is purulent In 



^Hhft?"^ t ""r*^' 1 '*^T^'? ^^^ ^?^"'*"^^ tl^^ ^^^^^late is mixed 

 with food or intestinal contents and in cases where the perfora- 



exTd^f. ''^''^ '\''-^^ ^^' '^'''^^^' '' '^''^''''- I^ any case the 

 exudate may coiitam a larger or smaller proportion of blood 

 Chronic peritonitis is characterized by the formation of connect 

 tve tissue. The encapsuled abscesses in cattle and pigs due to 

 A^!'V7 ^'^^^^ bacillus pyogenes are produced in this way. 

 Apait from this, acute fibrinous peritonitis usually becomes 

 chronic with the development of connective tissue undei the 

 fibrinous membranes. The peritoneum becomes thickened and 

 the surface of tlie organs is covered with thick layers of con- 

 nective tissue. Both these forms are seen very often in the 



