238 Rinderpest. 



to three days, then kept for 4 or 5 days in a shady place, also bone marrow after 

 the bono has been dried for 30 days, may still contain infectious virus. By heating 

 to 58-60°C. it is (lestroye<l innnediately, while a temperature of 20-25°C. destroys its 

 virulence only after it has been subjected for a longer period. Blood becomes 

 avirulent when subjected to a temperature of 37°C. for 2 to 3 days (Theiler). 



According to older data the virus is destroyed very slowly by putrefaction. 

 Thus meat which has been buried for three months is supposed to have been still 

 infective (Vicq D'Azyr). Arloing, however, found that the virus retains its 

 virulence in meat only for 4 days. The infectiveness of manure which has been 

 contaminated with the excrements of affected animals contains the virus for one 

 month, according to Bouley, and according to Krajewski it may sometimes be 

 infectious even after five months. More recent investigations in this direction 

 proveil, however, that the virus is destroyed by putrefaction in a few days (Kolle). 



Besides glycerin carbolic acid (2%), sublimate (1-1000), milk of lime (1%) 

 are effective as disinfectants; on the other hand, the virulence of the blood is not 

 modified by a %% carbolic acid solution (Kolle). 



Natural infection results either by direct contact with 

 affected animals or is transmitted through the raw products of 

 such animals, such as parts of carcasses, as Avell as by persons 

 contaminated by such carcasses or by infected secretions and 

 excretions. Food, drinking- water, stable utensils, clothes, etc., 

 may also transmit the infection. In most instances, however, 

 the infection is disseminated by affected animals in the ordinary 

 traffic with cattle, which mode of transmission is the more im- 

 portant as some animals may be only very slightly affected and 

 yet retain the virus in the body for 14 days, in chronic cases 

 probably even somewhat longer (Stockman; the maximum time 

 in which the animal mav be infectious for others is supposed 

 to be 30 days). 



The infection usually occurs through the digestive tract, 

 probably through the l^anph spaces, even of healthy mucous 

 membranes. The possibility of infection through the air pas- 

 sages has not been positively established, as it is questionable 

 whether the contagion is disseminated through the air. Out of 

 doors the spread of the disease may be prevented by digging 

 a trench around the infected herd which the animals are unable 

 to pass, and in such cases cattle on the other side of the trench 

 remain healthy (Raupach). Likewise it is possible to prevent 

 its spread by isolating affected cattle for a distance of 10 

 meters, when it will be found that healthy animals will not 

 contract the disease (Piot-Bey). In the stable healthy cattle 

 may be protected from the neighboring infected animals by 

 simple board partitions (Nencki). 



The susceptibility is very great in cattle, especially in the 

 young animals, although there appears to be considerable differ- 

 ence in the various breeds. According to some authors ( Jessen, 

 Haupt) cattle exposed to the infection become affected as a 

 rule without consideration of the breed. Some Russian authors, 

 however, claim that the long horned ranch cattle are less sus- 

 ceptible to the infection than the breeds of Western Europe. 

 Cattle of the gray breeds show a greater resistance to artificial 

 infection, and the course of the disease in them is usually milder. 



According to Remmer only 5 to 10% of ranch cattle succumb to an artificial 

 infection with virulent virus; against 90 to 98% of other breeds. Nicolle & Adil-Bey 



