582 



PRINCIPLES OF VETERINARY SURGERY 



Generally, their contents are expelled at the end of a certain 

 time, in consequence of ulceration of the skin covering them. 

 It is probable that these cysts are the result of an enclave- 

 ment of the branchial fissures. Quenu believes that in ad- 

 dition to the theory supported by Verneuil there is an epi- 

 thelial involution. But these theories do not explain the 

 dermatoid cyst of the ovary. 



TREATMENT.— The treatment is purely surgical. Ex- 

 tirpation, when possible, and at other times tapping, followed 

 by injections of irritating substances into the cavity with 

 the' purpose of modifying the wall and promoting their ad- 

 hesion. This last process is usually employed. The tap- 



FiG. 90. 



Non-Striated Myoma. Nuclei Stained with Carmin. The Round Forms are 



Transverse Section through the Long Elements. 



ping is performed with a small trocar. The skin is shaved 

 and washed, the trocar singed and then inserted into the 

 cyst. When the contents flovv out the solution selected is 

 injected slowly, as the cyst is gently massaged with the 

 fingers to bring the liquid into contact with every part of 

 the sac. The excess of the "solution may "be drawn away, 

 and then a protective dressing is applied to the surface. 

 After a few days the sac begins to fill with granulations and 

 the different parts adhere as the tumor disappears. 



