350 



VETERINARY PATHOLOGY. 



lively thin, though it is tough. Secondary tubercles may develop 

 from a primary tubercle, and daughter tubercles may develop 

 fmrn a secc.ndary tuliercle, thus are produced the irregular nodu- 

 lar tubercular masses. The tissues cuntiguous to a tubercle are 

 ischemic, iirnbabh- because of the enfringement of the affected 

 areas with lymplmid cells. 



Little difference is noted in tubercular lesions in the various 



^•y 



^3 





if 



1 I / 



i I, 



y. 



ir/'^O 3> <6 ® A 



)ft 



' ( 



C---^, 



Fig. 195. — A Lesion of Tuberculosis from tlie Post-pharyngeal L.Tiiiph Gland of an 



O-v. .\ — ^iunt-ti'lls; b — caseous center within the tubercle; c — fibrous capsule, 



tissues except possibly osseous tissue and serous membranes. 

 Tubercular lesions of osseous tissue are usually associated with 

 extensive suppuration of the osseous structures, while tubercular 

 lesions of serous membranes are frequentlv entirely cellular in 

 structure and do not undergo central necrosis. 



Bovine tubercular lesions are usually encapsulated and become 

 (piite extensi\-elv calcified. The age of the lesions is sometimes 

 important in medico-legal cases. Calcification usually begins 



