336 



\'eti:rinarv pathology. 



or excretion, e. g., renal cysts ; 2. By excessive secretion into duct- 

 less structures, e. g., distension of bursae ; 3. By extravasation 

 into the tunica vaginalis sac, e. g., hematocele ; 4. Li(|uefying 

 necrosis, e. g., formulation of cysts in the cerebrum of horses 

 affected with "blind staggers." 5. Parasites, e. g., C_ysticercus 

 cellulosae. 



Structure. — llie cystic wall varies according to the age of 

 the c^•st. In the beginning it may represent the original gland 

 structure or a cnndensation of the normal tissue of the part. 

 Later the cystic walls may be lineil with epithelium or endothel- 

 ium, \vhich acti\'elv secretes as long as the cyst grows. The cys- 

 tic ca]isule mav be composed entirely nf fibrous connective tissue. 

 In srime mstances the primar^• ca])sule is fibrous and later an 

 endiithclial lining dcvelnps. The c\'st A\all ( ir caj)sule ma}' be 



al n-;;inn nl 



