324 Veterinary Medicine. 



breathing may be absent ; the temperature may be almost reduced 

 to the healthy standard, the pulse small and tolerably soft, the 

 appetite considerably improved and the different secretions toler- 

 ably normal ; yet the pinching of the intercostal spaces causes 

 sharp pain, and measurement, auscultation and percussion testify 

 to the persistence of disease. The animal is hidebound, un- 

 thrifty and unequal to any exertion. The cough is weak and 

 painful and sometimes accompanied by a grunt. 



Besides the changes connected with exudation and effusion, 

 and organization or suppuration in the exuded products, gangrene 

 sometimes results. A case of this kind is related by Percivall. 



The duration of pleurisy may thus extend from two days in 

 very acute cases to several weeks, or even months if we estimate 

 it by the continuance of hydro-thorax in the chronic cases. 



Post Mortem Appearances. These consist mainly in the pres- 

 ence of false membranes, lining the pleura and hanging in cobweb 

 like shreds into the cavity of the chest, and of the liquid effusion 

 which fills up the chest at its most dependent part. The peri- 

 cardium also contains fluid in many cases. The successive 

 changes are as follows ; ist. Capillary dilatation causing arbores- 

 cent congestion of the pleura, with punctuate redness at intervals 

 inefaceable by pressure ; 2d. Swelling, proliferation and dis- 

 quamation of the epithelium, roughening and drying the sur- 

 face ; 3d, and sometimes in 24 hours, exudate into the serosa, 

 with formation of embryonal cells, a sero-fibrinous effusion into 

 the pleural cavity, and the coagulation of the fibrine, first on 

 the inflamed surface as false membrane ; 4th. The false mem- 

 branes are encreased layer upon layer, may become torn or 

 shreddy, cause morbid adhesions, or compress and condense the 

 lung. They become vascular and form white fibrous tissue, 

 from within outward by a process comparable to granulation in 

 an ordinary sore. The periods at which exudation takes place, 

 and when the principal changes take place in the exuded 

 materials have been well investigated by Dupuy, Hamont, Dela- 

 fond and St. Cyr. They induced pleurisy by injecting irritant 

 liquids into the chest, and noted the regular sequence of changes. 



Dupuy injected two drachms of oxalic acid dissolved in three 

 ounces of water. Symptoms of pleurisy at once came on, with 

 the friction sound characteristic of its early stages. Next day 



