176 THE DISEASES AND DISORDERS OF THE OX. 



disease. It is due generally to actual loss of the power of breath- 

 ing, sometimes to pulmonary gangrene. A fatal termination 

 may be precipitated or hastened by a sudden distension of the 

 rumen by gases, a result of the arrest of digestion. Thereby, the 

 lungs, already fearfully handicapped, are still more markedly 

 impeded, and asphyxia is the result. 



In some cases the animal may linger on for a long time. The 

 sunken eyes discharge an offensive secretion, and the animal 

 wastes day by day. The temperature sinks to a very low 

 point. Among the putrid pus which is expectorated portions of 

 disintegrated lung are coughed up. 



Post-mortem Appearances. — In the case of animals which have 

 died rapidly, the lung tissue is red or even black, loaded with a 

 great quantity of serum, and very soft and easily broken. The 

 chest may be opened by an incision, say into an intercostal 

 space. The ribs being broken at their union with the spine 

 above, and with the breast-bone below, a yellowish fluid 

 flows out from the cavity of the chest. This fluid contains 

 much albumen, and is liable to form a gelatinous clot if it is 

 exposed to the air. It varies in amount from a few ounces to 

 several gallons. This flow of fluid is seen in those animals 

 which have died when the disease is well advanced. Large 

 flakes of a yellow fragile substance float in this liquid. Further, 

 if the chest be opened by the divided portions of the sides of 

 the chest being raised, at certain parts the inside of the chest- 

 wall is found to be adherent to the lungs, these latter organs 

 being tied to the inner surfaces of the ribs by means of larj^e 

 deposits of the same yellowish friable substance which floats in 

 the liquid. The pulmonary pleurae (the layers which line the 

 lungs) are nearly always thus invested with a firm, solid layer 

 on one or both surfaces. These layers constitute the so-called 

 "false membranes." If the layer on the lung's surface is 

 stripped off, the lung is left rough and dotted with small 

 eminences. The lining membranes of the lung and of the chest- 

 wall, where not connected, have a dull appearance, and both are 

 covered by a layer of fibrin. The tissue beneath the pleurae, 

 which is continuous with the bands separating the lobules, is 

 also infiltrated. 



These membranes largely consist of ** fibrin," being sometimes 

 spoken of as coagulable lymph, but better called coagulated 



