PATHOLOGY OF DOURINE WITH SPECIAL REFER- 

 ENCE TO THE MICROSCOPIC CHANGES IN NERVE 

 TISSUES AND OTHER STRUCTURES 



By Robert J. Formad 



Pathological Division, Bureau of Animal Iitdtistry, United States Department of 



Agriculture 



Within the last five years on an average of from 45,000 to 50,000 

 complement-fixation tests have been made annually by the Bureau of 

 Animal Industry for the diagnosis of dourine. The samples have been 

 forwarded from Montana, North Dakota, South Dakota, Nebraska, 

 Wyoming, Arizona, and New Mexico, especially from the Indian reserva- 

 tions in those States. Many improvements have been made in perfecting 

 the technic of the complement-fixation test, thus affording better means 

 of diagnosing dourine, which is the most essential factor in eradicating 

 the disease. Diagnosis is the chief aim ; but while all energies are directed 

 toward that end other phases of dourine should not be overlooked, since 

 they may help to explain directly or indirectly the variations in existing 

 symptoms and the ciianges produced in the course of the disease. A 

 careful perusal of the literature on this disease reveals the fact that in 

 most articles on dourine the clinical picture — etiology, symptoms, and 

 treatment — receives more attention than the pathological phase, the 

 microscopic changes. These changes are often disposed of in a few 

 sentences or short paragraphs, quoted usually from the older European 

 descriptions of the microscopic findings. Very little consideration and 

 study has been given in this country to determine whether microscopic 

 changes as described in European cases of dourine are identical or 

 different. 



The object of this paper is to describe the microscopic lesions found in 

 nerv^e tissues and other affected parts. The materials studied was taken 

 from several well-developed chronic cases of dourine in horses from 

 Montana and Iowa in which the disease had been recognized clinically 

 and the animals had reacted to the complement-fixation test. The 

 animals were shipped to the Bethesda, Md., experiment station of this 

 bureau and kept under observation for nearly two years until they died. 

 On post-mortem examination these animals showed lesions of dourine. 

 An attempt will be made in this preliminary paper to correlate the 

 clinical symptoms with the microscopic findings. In fact, the clinical 

 symptoms afford chief guidance in selecting the tissues in which the 

 structural changes were studied. 



Journal of Agricultural Research, Vol. X\'III, No. 3 



Washington, D. C. Nov. i. 1919 



sq Key No. A-50 



(145) 



