24 GENERAL ACTIONS OF DRUGS 



emetic, or tepid water. If vomiting is due to acute irrita- 

 tion of the stomach, as is frequently the case in dogs, ice 

 and bismuth subnitrate (gr. x.-xx.), with tincture of aconite 

 (Tfl-i.-ii.), form suitable remedies. When vomiting arises from 

 indigestion and fermentation, carbolic acid with bismuth 

 often act favorably. The vomiting following anaesthesia is 

 probably of central origin. Here enemata of laudanum 

 (Tr[.x.-xxx.) and sodium bromide (gr. xx.-xxx.) are beneficial. 

 Ipecac, iodine, silver nitrate and the like are useful in vom- 

 iting dependent upon an atonic or depressed state of the 

 stomach. When vomiting is continuous, small quantities of 

 milk and lime water, equal parts, or peptonized milk 

 ( 3 ii.-iv.), or a drachm of cracked ice with a few drops of 

 brandy, should be given at half-hour intervals. It may be 

 rarely necessary to resort to rectal feeding. 



Purgatives c/r cathartics are agents which empty the 

 bowels. They act : (1) By stimulating peristaltic action. 

 (2) By increasing the secretions (succus entericus) of the 

 intestinal glands and, perhaps, transudation of fluid from 

 the blood vessels in the walls of the intestines. (3j By hin- 

 dering absorption of secretions and fluids which normally 

 occurs in the lower bowels. (4) By a combination of two or 

 more of these methods. Purgatives may be divided into : 



1. Laxatives. — These include such agents as : 

 Olive oil Nux vomica 



Cottonseed oil ^^^^^ ^^^ i small dose 



Magnesia Linseed oil j 



Sulphur 



These drugs slightly increase intestinal action, chiefly 

 by stimulation of peristalsis. 



2. Simple Purgatives. — These stimulate secretion and 

 peristaltic action. Among them may be mentioned : 



Aloes Rhubarb 



Calomel Senna 



Linseed oil Cascara sagrada 



Castor oil Frangula 



3. Drastic Purgatives. — Drastics are essentially gastro- 

 intestinal irritants, and in large doses cause mucous and 



