384 PERICARDITIS. ] 



The quantity of liquid also varies within very wide limits. There 

 may be scarcely any exudation. In that case the pericarditis is of a 

 partially adhesive character, with abundant false membranes. As aj 

 rule the quantity of fluid exudation varies between seven and eight 1 

 quarts, but sometimes the quantity is much greater. Trasbot de- ] 

 scribed an instance in which the united weights of the heart and peri- \ 

 cardium exceeded 36 lbs. Hamon mentioned a case of pericarditis in | 

 which the liquid exudate exceeded twenty quarts. j 



When inflammation is first set up the liquid is serous, yellowish, 1 

 or reddish-yellow. It contains fibrinous flocculi in suspension. Little I 

 by little this exudate becomes purulent, whilst the internal layers of the i 

 pericardial serous membrane undergo desquamation. These are next i 

 covered with false membranes of varying appearance ; the fibro-albu- J 

 minous exudation is wrinkled, villous and tufted. The two layers of | 

 serous membrane are connected at certain points by this exudation, the 1 

 adhesions being sometimes very extensive. The pericardial sac pro- \ 

 perly so called becomes the seat of marked lardaceous thickening,- due I 

 to inflammation. The heart appears entirely covered with a layer of \ 

 greyish or earthy-coloured granulation tissue, which appears as though ] 

 baked, and was compared by Hamon to the back of a toad. It is atro- 1 

 phied as a consequence of prolonged compression. \ 



Under the influence of the excentric pressure of the liquid the peri- j 

 cardial sac is distended and comes in contact with the walls of the chest, \ 

 to which it may adhere. The foreign body, especially if small, is not \ 

 always easy to find. ! 



The myocardium often displays interesting lesions. At first there is 1 

 thickening, or more commonly sclerous degeneration, of the superficial ] 

 layers covering the ventricles, and then appears a crop of little miliary 1 

 abscesses. Abscesses of considerable size have several times been | 

 detected in the walls of the ventricles and in the interventricular j 

 septum. I 



The foreign body, moreover, may not only injure the myocardium, | 

 but may even perforate it completely and produce ulcerative endocarditis \ 

 (Cadeac). In this case infectious germs very rapidly invade the circu- 1 

 lation and all the tissues, and the animal dies of pyaemia. j 



These essential lesions are accompanied by others of varying im- i 

 portance. Thus the lung is congested throughout, and by contiguity \ 

 of tissue inflammation may extend from the pericardium to the lower ^ 

 part of the pulmonary lobes and to the pleura. 



Interference with the return circulation induces lesions due to venous \ 

 stasis : dropsy of the chief serous membranes, oedema of the connective i 

 tissue, pleural and 'peritoneal exudations, etc. If the hind limbs never ] 

 become swollen it is because the skin covering them is very resistant \ 



