MAKING THE INJECTION. 



145 



Vessel. 



fine forceps by wliicli tlie edge of the incision is grasped. As soon 

 as the canula is in the vessel, let go the edge of the slit and grasp 

 the whole vessel where it sheaths the cannla. Pinch quite firmly, 

 and pull while the canula is pushed into the vessel for about 1 cm. 

 The canula being smooth slips into the vessel notwithstanding the 

 pressure of the forceps. Rest the elbows on the table to steady 

 the hands. 



The canula should be very smooth, and the serrations on the for- 

 ceps must not be too deep or they will cut the vessel. The canula 

 may be polished as directed for instruments 

 {§ 183), and any roughness may be removed 

 by the oil stone. 



As soon as the canula is properly in- 

 serted, put the thread nearest the incision 

 (Fig. 40) so that it will press on the canula 

 within the vessel, and then tighten the knot. 

 If the canula has an enlargement near the 

 end (Fig. 36, A), it cannot escape when tied as 

 in Fig. 42. If there is no enlargement or a 

 glass canula is used, the thread must be tied 

 to some part of tlie canula outside the vessel. 

 If there are transverse projections (Fig. 36, 

 A), the thread should be tied around one of 

 them. If a glass canula is used, tie as shown 

 in Fig. 42. All the threads should be knot- 

 ted in a hard knot finally, and the ends 

 should be cat within a centimeter of the last 

 knot. 



§ 359. Making the Injection. — As soon 

 as the canula is secured in the vessel, fill the 

 syringe partly with water or normal salt solu- 

 tion, connect it with the canula in the vessel, and force a little of 

 the liquid in to make sure the canula is open and properly inserted. 

 In connecting the canula and syringe, grasp the canula with one 

 hand and hold it firaily while making the connection. Do the same 

 in separating them. 



After forcing a small amount of water into the vessel, separate 

 the canula and syringe, expel the water, and then prepare the mass 

 as directed above (§ 345). Stir the mass thoroughly, and then fill 

 the syringe, being sure to lower the s^alnge as the mass is drawn 



10 



Canula of 

 surinoQ/ 



Fig. 42. — Inserting and 

 Securing Candla ; x 5. 



