CONTAGIOUS PLEUEOPKEXJMONIA. 375 



membranes of the thorax, or the}' may be confined to the parencliyma 

 of the lungs ; they may affect a whole lobe, or only a small portion of 

 it; they may or may not cause the so-called marbled appearance. 

 In the same way bronchopneumonia may vary as to the parts of the 

 lung affected, the extent of the lesions, the degree and kind of 

 fiathological changes in tlie interlobular tissue, the color of the lung 

 on cross section and the amount of hepatization. In individual cases, 

 tlierefore, it is often necessary to take into account the history of the 

 animal, tlie course of the disease, and the communicability of the 

 affection before a diagnosis can be made between the two diseases. 



Prevention and treatment. — The prevention of pleuropneumonia, 

 • as of other contagious diseases, consists in keeping animals so that 

 they will not be exposed to the contagion. As the disease arises only 

 by contagion, there is no possibility of an animal becoming affected 

 with it unless it has been exposed. If, therefore, pleuropneumonia 

 exists in a locality the owner of healthy cattle should make every 

 effort to keep his animals from coming near affected ones or which 

 have been exposed. He should be equally particular not to allow 

 persons who have been on the infected premises to visit his own 

 pastures, stables, or cattle. 



If pleuropneumonia breaks out in a herd, every animal in it should 

 be slaughtered, the stables thoroughly cleaned and disinfected, and 

 no other cattle allowed on the premises until a period of 90 days has 

 elapsed. 



Medical treatment of affected animals is unavailing and should not 

 be attempted. Xo matter how valuable the diseased animals may 

 have been before they contracted the disease, they should at once be 

 destroyed and the contagion eradicated. This is the best policy for 

 the individual as well as for the community. 



The eradication of this disease by local or National Governments 

 can be successful only when the same principles are adopted and 

 carried out as here recommended for individual stables. It is then a 

 difficult undertaking, simply because the contagion is generally 

 widely disseminated before any measures are adopted, and because 

 a great majority of cattle owners will never report the existence of 

 the disease. Regulations must therefore be enforced which will in- 

 sure the prompt discovery of every herd in which the disease ap- 

 pears, as well as the destruction of all diseased and exposed animals 

 and the thorough disinfection of the premises. 



To discover pleuropneumonia sufficiently early for this purpose, 

 the district supposed to be infected should be clearly defined and 

 inspectors should be constantly employed to inspect every herd in it 

 at least once in two weeks, or, better, once a week. No bovine animal 

 should be allowed to go out of the defined district alive, and all 

 which enter it should be carefully inspected to insure their freedom 



