DISEASES OF THE PLEURA; PLEURISY 149 



and when it does occur it is always accompanied by a high remittent 

 fever. 



The general health is very much disturbed. The animal Is stiff 

 and sore on moving about; has little or no appetite, but intense thirst. 

 The visil^le mucous membranes are reddened and congested, and in cases 

 where there is much exudation, the membranes are dark bluish-red. 

 The faeces are dry and hard. The urine presents some symptoms that 

 are diagnostic; for instance, while the exudate is forming and collecting, 

 the urine is scanty and thick and albuminous in reaction. When the 

 exudate is commencing to be reabsorbed the urine increases very much 

 in quantity and is very clear or whitish-yellow (see chapter on Examina- 

 tion of the Urine). 



There is also marked dyspnoea. In dry pleuritis the respiration is 

 superficial and rapid, and where there is great exudation the respirations 

 are short and painful and the animal has all the symptoms of smothering. 

 A characteristic symptom is the way the animal endeavors to assist 

 respiration by assuming a sitting position with the front legs spread out 

 as far apart as possible and using the abdominal muscles, with show of 

 pain on pressure of the abdominal muscles of the affected side. The 

 animal has a soft, dry, weak cough; this may, however, be absent. 



The physical symptoms are characteristic. On percussion at the 

 onset of the disease there is little change of sound, but when the exudate 

 has reached a certain height, the lower parts of the chest give a dull 

 sound which seems to be limited in a straight line, according to the posi- 

 tion of the animal. Above the exudation the sound is tympanitic on 

 account of the retraction of the lung. Auscultation gives a friction bruit 

 in the onset, and when the fluid begins to be reabsorbed and the pressure 

 of the exudate against the lungs is lessened, the respiratory bruit is 

 altered. In the earliest stages of the disease the sounds are vesicular, 

 but as the exudate collects the sounds become indistinct or blowing and 

 finally only bronchial, and when the bronchial tubes are affected the 

 sound is lost entirely. In the healthier parts of the lungs we find in- 

 creased vesicular breathing. 



Course and Prognosis. — Primary pleuritis is generally slow in its 

 course; the time taken by the exudate to become reabsorbed is very long, 

 except in very young animals, unless it is removed in an operative way. 

 When the exudate commences to be reabsorbed the percussion sound 

 becomes less dull and the respiration bruit more distinct, and if the exu- 

 date becomes quickly reabsorbed, the diseased side is lessened in cir- 

 cumference, or it can be better described as being flatter. 



Death may occur during the critical period of the disease by col- 

 lateral hypera^mia and cedema of the non-affected sections of the lungs, 

 by carbon-dioxide poisoning, from defective function of the lungs, by 



