INFECTIOUS DISEASES OF CATTLE. 



377 



such as are truly dangerous (foot-and-mouth disease, rinderpest, etc. ), 

 and causes temporary panics among stock owners. 



Rinderpest has its home, according to some authorities, in the terri- 

 tory around the Black Sea and the Volga River in Russia; according to 

 others, in Central Asia. Thence it has been conveyed it various times 

 by cattle to nearly every country of Europe and Asia, where it has 

 proved a veritable bovine scourge. It probably visited Europe as 

 early as the beginning of the Christian era, and the migrations of 

 people from the far East have since then introduced the disease from 

 time to time. Especially during the eighteenth century it was more 

 or less prevalent in Europe, owing to the frequent wars, during which 

 herds of cattle were brought from eastern Europe and Asia to supply 

 the demands of the armies. It prevailed in Europe during the Franco- 

 Prussian war. At present it exists in Russia, South Africa, and the 

 Philippines. 



The virus is conveyed from one country to another chiefly by means 

 of infected cattle, although infected hides, wool, and food may play 

 an important part in its dissemination. The railroad facilities of the 

 present, which furnish the means of such rapid communication, are 

 particularly liable to aid in the spread of the disease. 



In the past rinderpest has been supposed to be identical with various, 

 human diseases, among them smallpox and typhoid fever. These sup- 

 positions are unfounded, and the view of authorities to-day is that it 

 is a disease of a peculiar kind, not identical with any other known 

 infectious disease. 



The contagion of rinderpest. — The cause of rinderpest must be 

 looked for among micro-organisms — most likely bacteria. However, 

 the investigations made thus far for this causal factor have been 

 fruitless, although certain recent experiments would indicate that 

 the unseen microbe is of such dimensions that it is withheld by the 

 dense bacterial filters, but passes through the more porous ones. It 

 was formerly supposed by various authorities that rinderpest virus 

 appeared spontaneously under the influence of deteriorated food and 

 long and exhausting drives, also during unusual meteorological con- 

 ditions. This view, however, is no longer maintained. It is probable 

 that the disease in its home in Asia is perpetuated by continual infec- 

 tion of fresh animals, and some authorities even go so far as to believe 

 that the disease would be entirely stamped out, even in its native 

 haunts, by a destruction of all sick and infected herds. However this 

 may be, the success of such an undertaking would largely depend on 

 the nature of the cause. If a strictly parasitic organism, like the con- 

 tagion of pleuro-pneumonia, it might be completely extirpated in thie 

 way. If, however, the germs or bacteria may live and multiply out- 

 side of the bovine body, in the soil, water, or in some other animal, 

 extirpation would be impossible. 



The virus may be transmitted from sick to healthy animals in a 



