8 CIttCUMSTANCES MODIFYING THE ACTION OF DRUGS 



The ininimnm doses of drugs should be employed by 

 the subcutaneous method. 



INDICATIONS FOR SUBCUTANEOUS INJECTION. 



(a) To secure a rapid action, as in relieving intense 

 pain or motor excitement ; and to support, a failing 

 heart, respiration and vascular tone in severe operations, 

 anaesthesia, or other poisoning. 



(b) When administration of drugs by the mouth is 

 inadvisable or impossible, as in unconsciousness, dys- 

 phagia, convulsions or vomiting. 



(c) When a local as well as general action is benefi- 

 cial ; e.g., the use of strychnine iA roaring and other 

 local paralyses ; atropine in local muscular spasms ; 

 veratrine in muscular rheumatism. 



4. Intratracheal injection is a strictly veterinary pro- 

 cedure. The skin is incised aseptically with a sharp scalpel 

 midway in the neck, and a stout needle (attached to a syringe) 

 is thrust between the rings into the trachea. Larger quan- 

 tities [H.(3i.-ii.) (30.60.)] and more irritating drugs can be 

 given in this way than by the subcutaneous method, and 

 absorption is about as rapid ; the dose is the same. Some- 

 times this method is taken advantage .of to kill parasites 

 (S. fiiaria and micrurus) infesting the trachea and bronchial 

 tubes, and to influence the mucous membranes of the larynx 

 and trachea in inflammatory conditions. 



5. Drugs are icsually given by the mouth and are absorbed 

 from the stomach and intestines. Many non-irritating and 

 not unpleasant drugs are taken voluntarily in the food, 

 gruel, milk or drinking water by animals. Cats and dogs 

 will often swallow medicine enclosed in a piece of meat, 

 Absorption is more tardy than by the subcutaneous method, 

 more rapid when given in solution into an empty stomach ; 

 slower when administered in powder, pill or ball, and on a 

 full stomach. Some drugs are probably absorbed from the 

 stomach, only to be destroyed in part by the liver, or elimi- 



