432 THE dairyman's manual. 



infected cows. Without entering into any discussion of 

 the apparent causes of this disease — which enters into a 

 herd without previous notice or any premonition of dis- 

 aster, and goes through it, causing one cow after another 

 to lose her calf after periods of gestation of three to 

 seven or eight months, and which, having desolated the 

 farm for this year, reappears in the same herd or an en- 

 tirely new one, if the same stable and yards are used — it 

 will be sufficient to mention that none or all of the al- 

 leged causes of this disease will explain satisfactorily any 

 hypothesis or belief that any other conditions than the 

 introduction of a specific germ into an animal, or a herd 

 or stable, will reasonably account for the peculiar cir- 

 cumstances under which this malady makes its sudden 

 appearance in localities where it has never been heard of 

 previously. These circumstances are as follows : 



1. Abortion usually follows the introduction into a 

 stable or herd of some strange cow which is in calf and 

 which loses its calf without any apparent cause or prov- 

 ocation, Then one of the other cows loses its calf, a 

 second and a third follow, and the disease goes through 

 the whole herd. In a case known to the author of a 

 herd of seventy-two valuable Jersey cows, only seven live 

 calves were born in one year, and these were of cows 

 which had nearly completed their terms of gestation be- 



* fore the disease appeared. This infection followed the 

 introduction of a cow purchased at a public sale in Xew 

 York City, and this cow had lost her calf by abortion 

 the previous year. 



2. It is usually the cows nearest to the newly intro- 

 duced one which become affected, and the disease spreads 

 by the closest contact. 



3. When cows from healthy herds are brought into in- 

 fected herds or stables, those of them calving soon after 

 pass through their period safely, but those whose time is 



• more distant usually lose their calves. It thus appears 



