80 The Lung I'lague of Cattle. 



most earnest efforts of this kind. It may be conceded 

 that by means of inoculation the disease has been quickly 

 passed through indiyidual herds, and that when a country 

 or district makes inoculation universal that the mortalit;)' 

 is greatly reduced, yet the adoption of the operation for 

 healthy herds but multiplies the centres of infection, and 

 wlien a country is subjected to this, the plague is inevita- 

 bly kept up by the occasional contamination of young 

 and uninoculated animals. 



On the other hand, there are conditions in which inoc- 

 ulation is to be commended. On the steppes of Eastern 

 Europe and Asia, on the open lands of Australia and 

 South Africa, where herds mingle day by day and infec- 

 tion cannot be rooted out by any process of slaughter 

 and disinfection, the practice of inoculation is found to 

 reduce the losses to a minimum. In certain other condi- 

 tions the operation would be admissible. In the case of 

 large herds occupying insular or equally secluded locali- 

 ties, where the contagion is already widely diffused and 

 still spreading from beast to beast, it may be good policy 

 to inoculate the whole herd, and after recovery from the 

 inoculation to subject the whole to inspection and dispose 

 of any still showing traces of the plague. In such a case 

 all calves born in the herd must be either destroyed or 

 immediately inoculated as circumstances may suggest. 

 If calves are constantly coming their destruction will be 

 requisite, as a continuous inoculation will entail the 

 maintenance of the plague. In this M^ay such an insular 

 place might be cleared of the plague in a few months, 

 whereas the resort to a similar course in a thickly settled 

 disti'ict has always been shown to keep it up. 



Passing the Young theough the Plague. 



In some countries, where the plague is all but univer- 

 sally distributed, those running large dairies have found 

 it profitable to pass all their stock through the disease 



