354 Veterinary Medicine. 



lower piincta and its escape by the upper, and by the nasal ori- 

 fice, will determine the patency or otherwise of the various 

 channels. 



Treatment consists in astringent coUyria to check the inflam- 

 mation, in the removal of any foreign body, in the dilation or 

 slitting of the lachrymal canaliculi, and in case of complete 

 atresia, in incising the lachrymal sac. Slitting of the canaliculi is 

 accomplished by a small probe-pointed bistuory (canaliculus 

 knife). The lid is drawn away from the carnucle, and the probe 

 point inserted at first downward, then inward and backward, and 

 when it is well inside the sac the handle is brought to the vertical 

 and the walls of the duct slit open. 



In case of atresia Iv'eblanc recommends to seize the inner can- 

 thus with rat tooth forceps so as to include the structures about 

 the sac and to plunge the bistuory directly into the sac. Then 

 by the aid of a whalebone staff he passes three silk threads 

 through the duct and fixes them in place by attaching them to a 

 copper ring at each end. This is retained in place and moved 

 daily until the passage has been definitely healed and its per- 

 manency assured. 



WOUND AND FISTUDA OF THE I.ACHRYMAL SAC. 



The lachrymal sac, which receives the tears from the canali- 

 culi, is situated in the infundibulum at the upper end of the 

 lachrymal canal and is in great measure protected against exter- 

 nal injuries by the prominent orbital edge of the lachrymal bone. 

 Yet violent blows with, or without fracture, sometimes lead to 

 rupture of the mucous walls and the formation of a fistula. 

 Wounds made with penetrating bodies, more or less pointed are 

 also liable to involve the sac. The fistulous orifice may be through 

 the skin at the inner canthus or through the mucosa by the side 

 of the caruncle. The cutaneous opening may be a minute orifice 

 from which tears and muco-purulent matter escapes, to mat to- 

 gether the hairs on the side of the face. Sometimes there is a 

 reddish elevation, the size of a pin head, and in fistula through 

 the mucosa this is the rule, and the orifice is elevated so that the 



