602 PLEUROPNEUMONIA. 



walked through our streets, fall from sheer exhaustion, and 

 wait for hours by the roadside till they are carted away. If 

 we suffer from pleuro-pneumonia in cattle, we cannot say that 

 we attempt to avert any means by which it may spread. 



Symptoms. From the time that an animal is exposed to 

 the contagion to the first manifestation of symptoms, a cer- 

 tain period elapses ; this is the period of incubation. It 

 varies from a fortnight to forty days, or even two months. 

 Some credit may be given to reports of even longer periods 

 of incubation. During this period cows are found to thrive 

 fast, and often to yield much milk. The first signs, proving 

 that the animal has been seized, can scarcely be detected by 

 any but a professional man ; though, if a proprietor of cattle 

 were extremely careful, and had painstaking individuals about 

 his stock, he would invariably notice a slight shiver usher in 

 the disorder, which for several days, even after the shivering 

 fit, would limit itself to slight interference with breathing, 

 detected readily on auscultation. Perhaps a cough might be 

 noticed, and the appetite and milk secretion also diminish. 

 Though the amount of milk may not be much diminished at 

 first, I have heard milk-maids say that a clever milker can 

 tell in drawing that the cow is taken ill. The animal be- 

 comes costive, and the shivering fits recur. The cough be- 

 comes more constant and oppressive, the pulse full and 

 frequent, usually numbering about 80 per minute at first, 

 and rising to upwards of 100. The temperature of the body 

 rises, and all the symptoms of acute fever set in. A moan 

 or grunt, in the early part of the disease, indicates a danger- 

 ous attack, and the alae nasi, or nasal cartilages, rise spas- 

 modically at each inspiration ; the air rushes through the 

 inflamed windpipe and bronchial tubes, so as to produce a 

 loud coarse respiratory murmur ; and the spasmodic action 

 of the abdominal muscles indicates the difficulty the animal 



