SUBCUTANEOUS INJECTIONS. 



633 



method of injection is not suitable to cases in which the mucous 

 membrane of the intestine is in a state of irritation (Guinard). 



By Subcutaneous (Hypodermic) Injection. 



In this way, exactness in the amount of the dose can be insured 

 better than hy the mouth or rectum. With " difficult " horses, it 

 is often easier to make a subcutaneous injection, than to give a 

 ball or drench. This method is frequently indispensable for pro- 

 ducing local effects, as, for instance, with cocaine (p. 608), in Avhich 



Fig. 155. — Read's Enema. Pump. 

 / 



case the injection is made deeper than usual, or it is made close 

 to the nerve on which it is required to act. Medicines given hypo- 

 deraiically do not come in contact with the food in the stomach 

 and intestines ; and they " escape the changes which many sub- 

 stances undergo in the liver, and hence act more certainly" 

 (Finlay Dun). Economy in drugs is a further item for considera- 

 tion. The chief disadvantage of this method is that it is not suit- 

 able for certain medicines, such as oily substances, which are very 

 slowly absorbed by the subcutaneous tissue ; bulky agents, like 

 Epsom salts ; and irritating drugs, like turpentine. The bad effect 

 due to the introduction of putrefactive material into the wound can 

 be entirely obviated by strict antiseptic measures (p. 70). 



