aO GENERAL ACTIONS OF DRUGS 



Cholagogues are serviceable in indigestion and constipation 

 with disordered hepatic functions, as shown by icterus, light- 

 colored faeces, etc. A more complete method of ridding the 

 blood of bile consists in the use of both an indirect chola- 

 gogue (to increase biliary secretion) and a direct chola- 

 gogue (to sweep it out of the bowels). The urea-forming 

 and glycogenic functions of the liver are not influenced to 

 advantage by drugs, with the exception of opium, morphine 

 and codeine, which lessen the amount of sugar in the urine 

 in Diabetes Mellitus. 



GENERAL USES OF PURGATIVES. 



1. To empty the bowels, — In this way are removed faecal 

 accumulations and poisonous matters resulting from bacte- 

 rial infection, and from fermentative and putrefactive changes 

 in the intestinal contents in indigestion. Foreign bodies, 

 bile, pathological discharges and intestinal parasites are also 

 expelled. 



Peristaltic action is quickened in chronic constipation, 

 while spasmodic and painful conditions (colic) are relieved 

 by ridding the bowels of the source of irritation causing the 

 trouble. 



2. To remove fluid from the body. — This effect is more 

 marked after the use of concentrated solutions of saline pur- 

 gatives and other hydrogogues. Concentration of the blood 

 and resulting absorption of dropsies of renal and cardiac 

 origin, or inflammatory effusions, can be accomplished by 

 these agents. 



3. To revvlse. — That is, to cause dilatation of the blood 

 vessels in the intestinal walls and so withdraw blood from 

 remotely congested areas, as in cerebritis. The drastics are 

 appropriate for this service. Pain and nervous phenomena 

 in other regions are sometimes benefited by the counter- 

 irritant action of drastic cathartics. 



4 To deplete, — Cathartics, particularly concentrated 

 saline solutions, deplete the body both locally and generally 

 by withdrawal of serum from the blood vessels. Purgatives 



