THE LACHRYMAL APPARATUS. 745 



Fig. 536.— Probe of Bowmann. 



FiG. 537.— Knife of Weber. 

 C. — On the Lachrymal Canal. 



The obliteration of the lachrymal canal may become necessary 

 in consequence of changes in the structure of its walls, or the 

 pressure made upon it by the surrounding parts. In the first 

 case, it occurs as the result of traumatic lesions, or of inflamma- 

 tion of the mucous membrane, the exudates accompanying it, and 

 the accumulation of thick secretions in the channel of the canal. 

 In the second case, it is due to severe rhinitis, swelHng of the in- 

 flamed mucous membrane of the nasal cavities, polypi, bony growth 

 of any kind, or in cases of dental caries. 



The symptoms are : Lachrymation, filling up of the canal, its 

 inflammation, and arrest of the flow of the tears through the 

 lachrymal opening at the nose. 



According to Professor Leclainche, there are four modes of 

 treatment for the relief of this trouble. 



1st. Opening of the natural tract and removing the cause of 

 the obstruction. — This is done by the catheterism of the canal by 

 means of fine probes, or by detersive injections forced through 

 the inferior opening in the nostrils; or, again, as practiced by 

 Director Trasbot, by insufflation. 



2d. Making an Artificial Tract. — If the point of obliteration 

 is situated near the lower opening of the canal, an artificial open- 

 ing can be made above it. To do this, Leblanc recommends the in- 

 troduction of a whalebone probe through the superior lachrymal 

 opening into the canal until the place of obstruction is reached when 

 a counter opening is made with a fine bistoury through the walls 

 of the canal. Two or three silk threads are then introduced into 

 the new passage between the two openings and left in place for 

 about twenty days. 



If the obhteration is in the bony portion of the canal, and 

 cannot be overcome with the silver probe, the perforation of the 

 lachrymal bone and an artificial fistula must be made. 



