INTRA-VENOUS INJECTIONS OF IODINE. 613 



in length being alone required. In large animals, and even in the dog, 

 the jugular is the vessel chosen. 



The vein is compressed at its lowest point until it becomes distended 

 and prominent, the needle is then introduced obliquely in the direction 

 of the vessel, the further wall of which must not be pierced ; the skin 

 is drawn slightly towards the head, and the needle gently passed in 

 succession through it, the subcutaneous connective tissue, and the wall 

 of the vein. 



Escape of blood through the needle shows that it has entered the 

 lumen of the vein. Should any doubt exist on this point — especially if 

 the horse has struggled meanwhile — the vein is again "raised" for an 

 interval of a few seconds and blood again caused to escape from the 

 needle. The latter is then grasped between the index finger and 

 thumb, the nozzle of the syringe attached to it, and the liquid slowly 

 injected. 



The bore of the needle being so narrow, passage of air need not be 

 feared, though even should a few small bubbles pass into the vein no 

 bad effects follow. 



