134 The Diseases of Animals 



action of the drug is much more rapid and certain. 

 Much smaller quantities of medicine are required to pro- 

 duce given effects than when given by the mouth. 

 Medicines to be given hypodermically should be suf- 

 ficiently diluted, so that they will not injure the tissues 

 nor cause severe pain. They must be free from sedi- 

 ment and germs. The hollow needle of the syringe 

 should be unscrewed and taken in the right hand ; the 

 skin in the region of the neck or shoulder is firmly 

 grasped with the left, and with the right the needle is 

 quickly pushed through it in a slanting direction. 

 Considerable force is required to push the needle 

 through the skin of the larger and older animals, but 

 the lack of resistance determines when the point is 

 through. The syringe is then screwed on the needle and 

 the medicine gradually injected. The medicine is injected 

 into the loose tissue beneath the skin, usually in the 

 region of the neck or shoulder, to avoid injury to the 

 operator by the animal's kicking or biting. For special 

 purposes, medicines may be injected into almost any 

 part of the body. 



In giving medicines hypodermically it is important 

 that the instrument be perfectly clean and that the 

 medicine be pure and well diluted. Under some con- 

 ditions, medicine may be injected into the trachea, or 

 windpipe, by inserting the needle between the rings of 

 cartilage of which this tube is composed. It should 

 be given in this manner only upon the advice of well- 

 qualified persons. In inserting the needle, care should 

 always be taken not to inject the medicine into veins 

 or arteries, nor to puncture delicate structures. 



