234 SPECIFICS FOR THE ALIMENTARY TRACT 



There are no sound therapeutic principles for the use of cho- 

 logogues as such, but it has been found that the presence of bile in 

 the intestine is necessary for the action of certain purgatives. 

 Buckheim and Stadelmann found that in the absence of bile, the 

 following drugs are quite inactive or at least very much less power- 

 ful than usual: podophyllum, jalap, scammony, rhubarb. It is be- 

 lieved that this is due to the solvent action of the bile, for Stadel- 

 mann found that if soaps were given with these agents their activity 

 returned and that in other cases even a slight modification of their 

 chemical nature was sufficient to restore their activity even in the 

 absence of either bile or soap. 



Similar results have been obser\'ed from other causes. Eor in- 

 stance, some of the pure principles of the purgatives are less active 

 than the crude drugs, because the impurities of the latter alter their 

 solubility. According to Cushny, this alteration of the solubility 

 may act in two ways : " If the principle is rendered too soluble, it 

 may be absorbed in the stomach and upper part of the bowel, and 

 therefore fail to produce purgation; on the other hand, it may be 

 rendered so insoluble that it fails to come into intimate contact 

 with the bowel wall, and therefore does not irritate it." According 

 to Tappeiner, the effects of such colloid substances as the bile and 

 gums is to delay the absorption of soluble substances as in the upper 

 part of the bowel and at the same time keep the insoluble resins in 

 suspension. 



It is suggested that some of the purgatives have a more specific 

 action upon the organism and increase peristalsis by action upon the 

 nerves controlling it. Thus senna, aloin, frangulin, colocynthin 

 and podophyllin cause purgation when administered either intra- 

 venously or subcutaneously, but it is believed that their action is 

 due to their excretion into the bowel which will be inflamed as if given 

 per OS. 



Finally there is some reason to believe that purgation may result 

 from reflexes arising from the stomach or skin or local irritation in 

 some part of the bowel ; and these reflexes in some cases must pass 

 through the central nervous system. Dixon says, " Any irritant in- 

 jected subcutaneously behaves as a purgative." 



General Indication for Purgatives. 



1. Relieve constipation. 



2. Remove irritants from the intestinal tract. 



3. Promote absorption. 



4. Remove waste products from the blood. 



5. Relieve cerebral congestion. 



6. Lower temperature in fever. 



T. Deplete the gastroduodenal mucous membrane. 

 8. In the treatment of hemorrhoids or piles. 



