INTRODUCTION. 



2 3 



alongside of the trachea just mesad of the jugular, as 

 indicated by the line d (Fig. 3). Having cut through 

 the muscle, two white cords are seen along either side 

 of the trachea. The mesal one may be red, as it is the 

 carotid artery. The lateral one, lying in the same sheath 

 with the preceding, is the vagus or tenth cranial nerve. 

 Separate the artery from the nerve and tie two cords 

 loosely around the vessel as in the case of the jugular. 

 Lift up the artery with the index finger (Fig. 4), and 

 make an oblique incision with the 

 scissors. The cannula with the con- 

 necting tube attached should then be 

 inserted caudad in the oblique cut of 

 the artery (Fig. 5), and the string s 

 drawn tight so as to hold the cannula 

 in place. The string st should then 

 be tightened to prevent the injection 

 mass from running out where the can- 

 nula is inserted. After stirring the red 

 mass, filling the syringe, and slipping 

 the nozle into the connecting tube the 

 operator should press slowly but con- 

 tinuously on the plunger until that 

 portion of the carotid cephalad of the 

 string st is w^ell distended. In a large 

 cat this will not occur until the syringe is nearly or quite 

 empty. When the vessels are full, the cannula is with- 

 drawn while the operator pulls on both ends of the string s. 

 The syringe must be washed out immediately, after which 

 the blue mass is well stirred and injected caudad into the 

 external jugular in the same manner as described for the 

 arteries. 



By making a slit about three inches long in the ab- 

 dominal wall a fold of the intestine may be pulled out 



FIG. 5. METHOD OF 

 INSERTING THE CAN- 

 NULA INTO A VES- 

 SEL. 



