Aug. IS, 1919 Bacterium abortus Infection of Bulls 245 



The weight of the mass of tissue was 53^ pounds. On section it was 

 found to consist of an outer wall or capsule of from iX to 2 inches in 

 thickness. This abnormal structure had evidently resulted from pro- 

 liferative changes involving mainly the connective tissue coverings of 

 the testicle. Firmly embedded in this external layer could be distin- 

 guished areas of tissue that upon microscopic examination were identified 

 as epididymis that had undergone severe inflammatory changes. The 

 cavity formed by this dense fibrous wall contained a considerable quantity 

 of a grayish -colored, semifluid material identical with the substance pre- 

 viously obtained by aspiration. Floating free in the cavity was also a 

 mass of tissue that was recognized as the remains of the testicle, it having 

 the same general form although somewhat reduced in size. Blood vessels 

 no longer communicated with the organ, and the serous membranes 

 which normally envelop it had seemingly been entirely obliterated. The 

 close resemblance existing between the semifluid substance and softened 

 portions of the testicle strongly indicated that the organ was undergoing 

 liquefaction necrosis. 



Microscopic examination. — The thick wall surrounding the testicle 

 consisted largely of dense fibrous tissue with a certain amount of round- 

 cell infiltration. Different portions of the epididymis which were em- 

 bedded in this mass showed extensive interstitial proliferation, which had 

 resulted in a wide separation of the tubules. Chronic inflammatory 

 changes were noted in sections from the testicle proper. Many tubules 

 were surrounded by zones of round-cell infiltration. There was exfolia- 

 tion and more or less disintegration of the epithelium lining the tubules, 

 causing the latter to be largely occupied by cell debris. Advanced 

 degenerative changes, verging on necrosis, were observed in all the sec- 

 tions examined, the peripheral portion of the organ exhibiting little more 

 than a mere outline of the testicle structure. 



BacterioIvOGICAl findings. — Tubes of serum agar that were inoculated 

 with the exudate at this time developed numerous colonies of an organism 

 that was identified as Bad. abortus. 



It has been suggested by writers on abortion disease that Bad. abortus 

 infection when acquired by bulls remains active for a comparatively 

 brief period, the resistance offered being sufficient for its destruction. 

 The encountering of a considerable number of animals giving slight 

 agglutination reactions and the isolation of abortus infection from only 

 a small percentage of the bulls cultured would tend to strengthen the 

 theory that the infection may commonly terminate in this manner. On 

 the other hand the extensive pathological changes and the chronic 

 character of the lesions exhibited by three of the five bulls where abortus 

 infection was demonstrated suggest that it may be unwise to assume that 

 long-standing cases of infection never exist. 



