INTRA-TEACHEAL INJECTIONS. 635 



should avoid hurting. The fluid is gradually forced out by the 

 pressure of the right thumb, and the syringe slowly withdrawn. 

 The first finger of the left hand is then placed on the orifice, to 

 prevent the fluid escaping, and the part which contains the fluid 

 is gently rubbed with the right hand, so as to hasten absorption. 

 It is sometimes more convenienr to disconnect the needle from 

 the syringe, insert it, and then screw on the nozzle, than to make 

 the puncture with the needle attached to the piston. If, while 

 injecting, we see a bubble of air in the piston, we should avoid 

 injecting it, by taking care not to press the piston " home." 



Fig. 1 56. —Hypodermic syringe. 



By the Windpipe. 



According to this (intra-tracheal) method, the medicine is in- 

 jected by the syringe through an opening in the windpipe. The 

 puncture should be made well away from the larynx, and in the 

 space between two adjacent cartilaginous rings of the windpipe, 

 and is generally effected by a curved trocar and cannula. On re- 

 moving the trocar, the nozzle of the syringe is fixed to the cannula, 

 the end of which should point downwards. The mucous membrane 

 of the windpipe is not very sensitive, probably on account of its 

 great power of absorption. The amount of solution may vary from 

 I to 1 oz., and the fluid should be slowly injected, so as not to in- 

 terfere with the breathing. The nature of the fluid and the 

 jDrecautions as to cleanliness are similar to those in subcutaneous 

 injections. " Beyond a slight gain in time, intra-tracheal injec- 

 tions, other than those intended to act locally, have no advantage 

 over hypodermic injections (Finlay Dun). This statement does 

 not hold good with respect to quinine, a solution of which is readily 

 absorbed by the w'indpipe and without producing irritation, which 

 it is apt to do if injected subcutaneously. Veterinary-Surgeon 

 Desmond, who has had a very large experience in the admini- 

 stration of eserine to horses, greatly prefers to give it intra- 

 tracheally than subcutaneously. 



