466 DIGESTION. 



the facial nerves and transverse facial artery are cut across as 

 -well as the duct. 



As soon as the bleeding has ceased, the discharge of saliva 

 from the cut end may be investigated in the manner directed 

 in 90. 



88. Investigation of the Secretions of the Salivary 

 Glands in the Dog. Permanent Salivary Fistulse. 

 Permanent fistula- may be made either with or without insert- 

 ing a canula in the duct. In the method to be described, that 

 ofSchifT, no canula is used. Permanent Submaxillary Fis- 

 tula. The animal having been placed on the table, and its 

 head secured with the aid of Bernard's holder, it is put under 

 the influence of chloroform. 1 Shave the hair from the under 

 surface of the lower jaw. Make an incision along the inner 

 border of the ram us of the lower jaw, extending forwards 

 from the anterior margin of the digastric muscle, and dividing 

 the skin and platysma. Secure every vein that presents it- 

 self with two ligatures, and divide it between them. Divide 

 the mylohyoid muscle cautiously. Underneath it will be found 

 the submaxillary and sublingual ducts, which run side by side, 

 the submaxillary being somewhat larger and nearer the ranuis 

 of the jaw. Isolate the duct and divide it as near as possible 

 to its entrance into the mouth. Close the wound with sutures, 

 leaving the entf of the duct projecting. To prevent its retrac- 

 tion, pass a Mituro through it. When the wound heals, the 

 end of the duct will come away, leaving a fistulous opening. 

 Kxamine it daily, and if it has a tendency to close, pass a fine 

 probe into it and along the duct. 



Permanent Suhlingual fistula. This is made in the same 

 way as a submaxillary fistula, and the same animal may be 

 used for both, but the two fistulae should be on opposite sides 

 of the head. 



89. Parotid Fistula. The animal having been secured 

 and placed tinder chloroform as before, the hair is clipped from 

 tin- cheek bet \veen the orbit and the angle of the mouth. On 

 running the finger along the lower border of the zygomatic 

 arch from behind forwards, its anterior and inferior root is 

 felt at its insertion into the superior maxilla, forming an arch, 

 of which the convexity is directed backwards. At the end of 

 this arch, between its insertion into the maxillary bone and 

 the alveolus of the second molar tooth, a little depression is 



1 In administering chloroform to a dog, groat care must be taken that 

 tin- vuMor is sufficiently diluted with air, and that the sponge does not 

 come into contact with the muz/le. The breathing must be carefully 

 watrln-d during the period of administration, and if it fails it must'be 

 continued liy alternately compressing and relaxing the thorax. If this 

 does not succeed, no time must be lost in opening the trachea and com- 

 mencing artificial respiration. \ 



