74 Veterinary Obstetrics 



present time, a period of twenty Ncars, it has not reappeared in 

 that territory. 



Since that time the affection has been recognized in Nebraska, 

 South Dakota, and in the province of Alberta, Canada. In these 

 areas of infection the disease has not been definitely traced to its 

 .source. Tlie outbreak in Illinois was believed to have been in- 

 troduced by stallions imported from France, a conclusion which, 

 although unproven, time has not served to change. The affected 

 area in Illinois produced considerable numbers of grade draft 

 stallions and mares, which were sold to go to the West and North- 

 west for breeding purposes, and, although it cannot be clearly 

 shown, there is good reason to conclude that this outbreak furn- 

 ished the infection for the others which have occurred in Amer- 

 ica. 



It has now become .so widely di.s.seminated, its eradication from 

 among range animals is so uncertain, and the po.ssibility of fresh 

 importation so apparent, that the malady is of great importance 

 to the horse breeding industry of America, since it may, possi- 

 bly, manifest itself at any time in any breeding district. These 

 facts render it important that veterinary practitioners, in horse 

 breeding districts, should be on the alert and ready to recognize 

 the disea.se in the early stages of an outbreak, ere it gains a wide 

 distribution and its eradication is rendered difficult and uncertain. 



Nature. Dourine is a highly infectious venereal disease trans- 

 mitted naturally by coition only. Experimentally, it may be trans- 

 mitted by innoculation and to other animals than solipeds. It is 

 due to a protozoan parasite belonging to the trypanosoma group. 

 This parasite, the tiypa^iosoviuvi eqiiiperduvi, was discovered by 

 Rouget in 1896 and its relation to the disease clearly demonstrated 

 by Schneidei and Buffard in 1899. Tlie trypanosome of Dourine 

 is a one-celled organism provided with a fiagellum at the anterior 

 end. It is about 18 to 26 microns in lengtli and, when observed 

 in the living state, is highly motile. It occurs in the blood, spinal 

 fluid, the discharges from the genital organs, in the plaques of 

 the skin and perhaps in other tissues and fluids of the infected 

 animal. It multiplies by longitudinal division. When removed 

 from an animal and kept moist, it will live for several days or 

 even a week. 



It is not always easily found. It is .said to be mo.st readily dis- 



