• Dourine. 569 



mice, asses. While the horse shows the greatest susceptibility, 

 the ass is comparatively very resistant to the poison. 



History. The malady has probably long prevailed in the east, 

 yet it was first clearly distinguished in 1796 when described by 

 Ammon as prevailing in the royal stud at Trakehnen in Northern 

 Prussia. We have later descriptions of the disease in the same 

 locality in 1801 (Hertwig), and 1807 (Ammon). It was found 

 in Bromberg in 1817 to 1820 (Waltersdorf), also in Hannover 

 (Haveman), in Austria and Bohemia in 1821-8 (Fischer), in 

 Styria in 1821, in Switzerland in 1830, in France in 1830-2 (I^au- 

 tour), in Silesia and Pomerania in 1833-40 (Fischer), in Italy in 

 1836, in Russia in 1843, (Fischer), in Silesia and Poland in 

 1830-40 (Freidberger and Frohner), in Algiers in 1847-55 ^'^'^ 

 in Syria and Asia generally and perennially (Daumas andSignol) . 



It appeared at Wapella, 111., in 1882, the first affected 

 animal being a brown stallion that had been imported from France 

 and which bore on his neck a brand like the letter D. In this 

 locality it extended to a considerable number of breeding mares 

 and stallions, and having been recognized by Dr. W. L. Williams, 

 was largely stamped out by a rigid quarantine of diseased and 

 exposed animals. Some exposed animals had, however, left the 

 district, and isolated centres of infection have been since found 

 in Nebraska and elsewhere in the United States and N. W. 

 Territories. 



It is not known to have invaded Belgium, Scandinavia, Eng- 

 land, South America nor Australasia. 



All indications point to Asia or North Africa as the primal-, 

 tome of the disease, as they still prove its perennial one. ? 



Causes. The disease is transmitted by contagion and almost 

 exclusively in the act of coition. Hayne has seen the affection in 

 geldings, and Haxthausen in mares that had never been served. 

 Schneider, Buffard, Nocard, Blaise and others have transmitted it 

 freely by inoculation of blood and nervous matter, so that the 

 possibility of infection through other channels than the generative 

 organs must be admitted. But such irregular means of casual 

 infection are so rare, and the probability of transmission of the 

 virus from a non-breeding animal is so remote that in the practical 

 measures of sanitary police, the breeding horses alone need be 

 taken into account. 



The extra vascularity of the male and female generative organs 



