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EXPERIMENTAL PH YSIOLOG Y 



the vein a. The other, V 2 , comes from its posterior aspect and 

 enters the vein p. Sometimes one vein is the larger, sometimes the 

 other. 3. Tie both branches of the lower division of the jugular a 

 little beyond v 1 . Tie the upper of the two branches where it crosses 

 the ramus of the jaw and remove the part between the ligatures. 

 4. Tie the other division (p) on the distal side of the place where it 

 receives the gland vein, v 2 . 5. Eemove the cellular tissue from the 

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

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

 the gland which runs forwards and inwards between it and the 

 masseter. 6. Separate the digastric muscle by means of a director or 



Fig. 170. 



-Relations of the Duct and Nerves of the Submaxillary 

 Gland in the Dog. (After Bernard.) 



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 



