Infectious Broncho- Pneumonia of Cattle. 287 



The walls of the bronchia show marked congestion and redness 

 with infiltration of the mucosa and submucosa. The muco- 

 purulent contents, filling the smaller bronchioles to repletion, 

 and the exudate which drains from the recently affected lung, 

 equally swarm with the specific bacillus, usually in pure culture. 

 The abundance of this microbe serves to complete the diagnosis 

 from lung plague, in which the exudate is remarkably clear and 

 free from granules and visible microorganisms. 



Prevention. As in all infective diseases the important consid- 

 eration is to keep susceptible animals away from the source of 

 infection, and as that attaches to certain localities and their 

 products in this disease, cattle should be denied access to these. 

 Infection from animal to animal should also be provided against, 

 yet this is of less account, as the disease is largely enzootic, and 

 though cases may be adduced in which contagion must be con- 

 ceded, yet, out of its primal locality, it has never shown a tendency 

 to spread without limit as do the epizootic lung plague and other 

 contagious diseases. It is not necessary, therefore, to surround 

 the infectious broncho-pneumonia of cattle with the elaborate 

 and unbending system of safe-guards which are demanded in a 

 true plague. The quarantine of the single infected herd will 

 usually put a speedy end to the trouble. 



