PATHOLOGIC LESIONS 443 



by inhalation, experiments to spread the disease by this method have 

 generally been unsuccessful. The virus may remain alive and active 

 for some time in stables where sick animals have been kept and it may 

 spread to new importations even after the disease has disappeared 

 among the stock by deaths or recoveries. If fluid containing the 

 microorganism of the disease is inoculated in a very small dose 

 into the subcutaneous connective tissue of cattle an edematous, 

 painful swelling appears after a variable number of days at the 

 point of inoculation, the temperature rises to 41 to 42 C., and 

 death occurs after a fall of temperature and a comatose condition 

 have set in. 



Protective Inoculation. This has been practised for many years, 

 first in an empirical manner, and in 1852 by Willems, who dipped 

 a vaccination lancet into the juice expressed from the alveoli of an 

 infected lung, and vaccinated in two or three places at the lower end 

 of the tail. Pasteur, in 1881 and 1882, used a lymph attenuated by 

 mixing the fluid from affected lungs with glycerin. A large number 

 of investigators have at various times attempted to devise an effective 

 protective inoculation. Raebiger, however, who has critically 

 reviewed the various methods, comes to the conclusion that their 

 protective value is problematical, that the danger of contraction of 

 the disease by non-immune animals from vaccinated animals is great, 

 and that the best method of limiting the disease consists in the slaughter 

 of all infected animals. If for any reason this is impossible, pro- 

 tective vaccinations by attenuated lymph or artificial pure cultures 

 may be practised. 



CATTLE PLAGUE. 



Occurrence. Cattle plague, contagious typhus, pestis bovina, or 

 Rinderpest (German), is a highly contagious, very fatal (60 to 90 per 

 cent, mortality) disease of cattle. It is very prevalent in various parts 

 of Asia, including the Philippine Islands, Africa, and is also met with 

 in Europe, in the southern parts of the Balkan peninsula, and in 

 southern Russia. The organism causing the disease is not known, 

 but it is probably of a type similar to that of contagious pleuro- 

 pneumonia. It appears that the virus contained in natural albumin- 

 ous body fluids does not pass the Chamberland or Berkefeld filters, 

 but that it does when such albuminous fluids are diluted with a sterile 

 watery fluid. 



Pathologic Lesions. The most characteristic pathologic lesions of 

 the disease which has a rapid onset are strong hyperemia of the con- 

 junctiva, fetid discharge from the nostrils, and hemorrhagic diar- 

 rhea. On postmortem examination the fourth stomach is found 

 strongly hyperemic, with petechise on the elevated margins of the 

 folds of the mucosa, and in the more chronic cases ulcerations are 

 formed. The intestines are covered with a fibrinous exudate, which 



