Pseudotuberculosis of Sheep. 635 



Dunkel, in his comparative investigations, arrived at the conclusion that the 

 bacillus pseudotuberculosis ovis and the bacillus pyogenes bovis et suis are varieties 

 of the same species because they are reciprocally agglutinated by their respective 

 immune sera; because mice, after treatment with one bacillus become immune to 

 the other, and further, because the Bacillus pyogenes after being passed through 

 the rabbit assumes the appearance of Bacillus pseudotuberculosis when inoculated 

 into sheep. Glasser also suspected a close relationship between the two bacilli 

 and in addition is inclined to look upon the bacillus of pseudotuberculosis of 

 sheep and that of rodents as varieties of the same species. Finally, according to 

 Nocard, Vallee, Panisset & Loiseau a certain rela'tionship existed between the 

 pseudotuberculosis bacillus and the bacillus of diphtheria of man, while Dunkel, on 

 the other hand, doubts the identity of the pseudotuberculosis bacillus and the 

 bacillus of ulcerous lymphangitis of horses, basing his belief upon an experimental 

 inoculation of a horse. As a result of these various views the proper classification 

 of the bacteria referred to is in such an unsatisfactory state that a thorough 

 revision of this question is very desirable. 



The natural mode of infection is as yet not definitely 

 known. Probably it occurs most frequently through the in- 

 testinal tract, and possibly also through the respiratory pas- 

 sages. The bacilli may also gain an entrance through wounds 

 of the skin and through the navel of newborn animals. In 

 older lambs infection may occur following amputation of the 

 tail, the germs entering the lymph channels of the subcutis. 

 The droppings of infected sheep seem to be a prolific means 

 of disseminating the disease, Carre having found large masses 

 of pseudotubercle bacilli in the droppings of apparently healthy 

 sheep. 



Anatomical Changes. In the majority of cases the morbid 

 processes even in animals that have died with symptoms of 

 cachexia is confined to the intrathoracic and the external lymph 

 glands, or to the latter only, while the mesenteric glands are 

 only very rarely affected. The glands appear to be considerably 

 enlarged and contain circumscribed foci, or they have become 

 transformed into greenish-yellow, sticky, smeary, cheesy masses 

 which may consist of concentric layers resembling the structure 

 of an onion, and surrounded by a thick connective tissue wall 

 with smooth inner surface. Subsequently lime salts_ are de- 

 posited in this caseous mass giving it a grayish-white color 

 and a mortar-like or gypsum-like consistency. 



In some cases small gray, or grayish-green nodules or even 

 large tumors of a structure similar to that of the cheesy glands 

 are found scattered through the lungs. 



In addition we may occasionally find diffuse, lardaceous, 

 indurated, lobar and lobular pulmonary lesions with soft, 

 greenish cheesy foci. This condition is usually attended with 

 an adhesive pleuritis and normal appearance of the regional 

 lymph glands (Sivori, Noack). 



Noack mentions, as a rare observation, oval groups of 

 nodules the size of a pea arranged in a manner resemblmg 

 coral, in the walls of the large and small intestines. Finally, 

 the liver, the spleen and the kidneys may occasionally contain 

 similar, cheesy or caseo-calcareous nodules. 



