242 OVINE LYMPH-ADENITIS 



afterwards. In the centre of the older purulent or caseous 

 mass (for the consistence varies from that of cream to that of 

 cheese in different tumours) there are usually present no bacilli 

 which can be demonstrated by the microscope or by cultural 

 methods. 



§ 171. Differential diagnosis. This specific lymphatic 

 affection is to be differentiated from : 



1. Infections of various kinds, not recognized as specific, 

 which may cause enlargement or suppuration of lymph glands. 



2. The specific infectious diseases, such as tuberculosis. 



3. Lyraphadenoma. 



If the diagnosis cannot be made from the gross appear- 

 ance of the lesions a bacteriological examination will be neces- 

 sary. The fact should be kept in mind that tuberculosis in 

 sheep is very rare. In lymphadenitis, cultures in ordinary 

 media will give a growth of the bacterium of Preisz. With 

 tuberculosis the results would be negative (see tuberculosis). 

 It is important not to confuse the nodular disease of .sheep's 

 intestines with this affection. The location of the lesions in 

 the walls of the intestine will be quite suflBcient to determine 

 the nodular disease. 



REFERENCES. 



1. Cherry AND Bull. Caseous lymphatic glands (pseudo-tuber 

 culosis) in sheep. The Veterinarian, Vol. LXXII, p. 523. 



2. EberTH. Bacillare Nekrose der Leber. Virchow's Archiv, 

 Bd. C (1885), p. 23. 



3. GiLRUTH. Pseudotuberculosis in sheep. (Lymphadenitis). 

 Jour. Compar. Path, and Thera., Vol. XV (1902), p. 324. 



4. GiLRUTH. Pseudo-tuberculosis in sheep. (Lympho-adeuitis). 

 Bulletin No. i. New Zealand Dept. of Agriculture. 



5. NoRGAARD AND MoHLER. The nature, cause, and economic 

 importance of ovine ca'^eous lymph-adenitis. Sixteenth Annual 

 Report, Bureau of Animal Industry, 1899, p. 638. (Full bibliography). 



6. Preisz and Guinard. Pseudo-tuberculose chez le mouton. 

 Jour, de med. de vet. et de zootech, ser. 3, Vol. XVI (1891), p. 563. 



7. Preisz. Recherches comparatives sur les pseudotuberculoses 



