28 GENERAL ACTIONS OF DRUGS 



most favorably are indigestion with constipation, with or 

 without icterus and clay colored stools. Such conditions 

 were formerly thought to be due primarily to disordered 

 liver or " biliousness," but the cases amenable to treatment 

 really arise in the beginning from functional disorder of 

 the stomach or intestines. The clinical value of so-called 

 cholagogues is therefore not at all disturbed— ronly the theory 

 accounting for their action. 



GENERAL USES OF PURGATIVES. 



1. To empty the howels. — In this way are removed 

 fsecal accumulations and poisonous matters resulting from 

 bacterial infection, and from fermentative and putrefactive 

 changes in the intestinal contents in indigestion. Foreign 

 bodi'es, 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 hydragogues. 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 revulse. — 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 



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