BY DR. LAUDER BRUNTON. 469 



usual precautions, the hair is clipped from the jaws and neck, 

 and the skin cleaned with a wet sponge. This having been ac- 

 complished, proceed according to the following 



Directions. 1. Make an incision along the inner border of 

 the lower jaw, beginning about its anterior third, a little in 

 front of the insertion of the digastric muscle v and extend it 

 backwards to the transverse process of the atlas, dividing the 

 skin and platysma (see, figs. 308 and 310). 2. Expose the 

 jugular vein at or near the point where it divides into two 

 branches (j' and j"), and lay bare those branches also. One 

 of them (j') passes upwards behind the gland ; the other 

 (j") passes forwards below it, and then subdivides into two 

 branches. The gland itself has two veins. One of them (d' 

 fig. 308) issues from its posterior aspect and enters the vein 

 j'. The other (d) comes from its lower side and enters the 

 vein j". Sometimes one vein (d) is larger, sometimes the 

 other (d'). 3. Tie both branches of the lower division of 

 the jugular opposite J" (fig. 310). Tie the upper branch 

 where it crosses the ramus of the jaw, and remove the part 

 between the ligatures. 4. Tie the other division (J') on the 

 distal side of the place where it receives the vein (d' fig. 308) 

 from the gland. 5. Remove the cellular tissue from the surface 

 of the digastric muscle, and from the groove between it and 

 the masseter. Be careful not to injure the facial artery, and 

 the duct of the gland which passes forwards and inwards 

 between the muscles. 6. Separate the digastric muscle by 

 means of a director or aneurism needle from the facial artery. 

 Tie the arterial twig which supplies the muscle. Separate the 

 muscle from its attachment to the jaw, or divide it about its 

 anterior third, cutting it through very carefully, so as not to 

 injure the duct and nerves which lie below it. 7. Lay hold of 

 the lower end of the digastric with a pair of artery forceps, 

 and draw it backwards. This brings into view a triangular 

 space, whose apex is directed forwards, and whose base is 

 formed by the reflected digastric. Its lower margin (the dog 

 being supposed to be in the upright position, as in the figures) 

 is formed by the genio-hyoid muscle, and its upper one by the 

 ramus of the jaw and the lower edge of the masseter. The 

 anterior half of its floor is formed by the mylo-hyoid muscle, 

 on which some nerves ramify. The carotid artery enters the 

 triangle at its lower angle, and runs along its base, giving 

 off first the lingual artery, secondly the facial. Just as the 

 carotid begins to pass in front of the digastric, it is crossed by 

 the hypoglossal nerve P, and is accompanied by filaments of 

 the sympathetic tt'. At the upper angle of the triangle, several 

 structures pass from it to the hilus of the gland close to the 

 margin of the digastric. These are 1, the duct; 2, the nerves ; 

 3, the principal artery of the gland. The artery is given off 



