TIME OF ADMINISTKATION 13 



ing that this amount is recommended as a suitable canine 

 dose in veterinary text books. 



Contrariwise, the dog is comparatively insensitive to 

 many drugs powerfully influencing man, — notably aloes, 

 colocyuth and rhubarb. Most cathartics act more quickly 

 on dogs than is the case with the other domestic animals, 

 but saline purgatives are less appropriate in often causing 

 vomiting, and because of their bulk. 



Time of Administration. 



This matter has been alluded to in speaking of the 

 absorption of drugs. Mediciues readily undergoing decom- 

 position in the presence of other substances, as iodine and 

 hydriodic acid, should be given on an empty stomach ; and 

 likewise all drugs, when a speedy action is desired. Irrit- 

 ants should be administered on a full stomach; while agents 

 requiring hydrochloric acid for their solution — as iron — 

 must be exhibited on the food or immediately after the 

 time of feeding. 



Habit. — This circumstance does not have the same import- 

 ance in veterinary medicine which it possesses in human 

 practice, since we control drug habits in animals. Animals 

 usually become less susceptible to the action of drugs 

 on their repetition, e.g., opium and cathartics. This rule 

 does not hold in the case of drugs having a cumulative 

 action, nor in the repeated use of irritants on the skin, for 

 then their action is strongly intensified. 



Disease. — The action of drugs is profoundly influenced 

 by disease. It is only possible to enumerate a few exam- 

 ples. Pain is almost an antidote to opium, and large re- 

 peated doses of the drug, previously innocuous, may, on the 

 sudden cessation of pain, induce poisoning. Opium is also 

 borne in enormous doses in peritonitis. Inflammation and 

 congestion of the digestive organs hinders the absorption of 

 all medicines. A congested condition of the alimentary 

 canal, and even of the respiratory tract in horses, contra- 

 indicate the use of strong purgatives in these animals, 



