DISEASES OF THE DIGESTIVE ORGANS 43 



collection of fluid and increased peristalsis occur as the result of 

 the action of any of the irritant cathartics which produce hyper- 

 emia, catarrh or inflammation in the intestinal mucous membrane. 

 In this group are included croton oil, tartar emetic, colocynth, jalap, 

 gamboge and other drastics. These drugs should not be prescribed 

 in acute inflammatory conditions of the intestines. 



(f) Intestinal tetanus, with rapid expulsion of the intestinal 

 contents, is the cause of the cathartic action of eserine, nicotine 

 and barium chloride and partly also of arecohne and pilocarpine. 



(g) Paralysis of the splanchnic, the inhibitory nerve of the 

 intestines, results in the acceleration of peristalsis. Atropine acts 

 in this manner. 



(h) Lubrication of the intestinal walls mechanically accelerates 

 the passage of the intestinal contents. This is the mode of action 

 of the fixed oils, but in part only of castor oil. 



Results of Catharsis. — Scarcely any other action of drugs is 

 accompanied by so many local and general effects as catharsis. 

 To begin with, the intestinal canal is emptied of whatever it may 

 contain: normal contents, fermented or decomposed food, calculi, 

 concrements, poisons, inflammatory products, parasites or infec- 

 tious materials. Secondly, peristalsis is accelerated and the 

 secretions of the intestinal glands increased. Some cathartics, 

 as aloes, rhubarb, colocynth and podophyllum, at the same time 

 increase the secretion of bile; these are called the cholagogue 

 cathartics. The withdrawal of fluid from the blood into the intes- 

 tines has the effect of condensing the blood, in consequence of 

 which the blood absorbs fluids from the tissues (hydragogue 

 cathartics). The volume of the blood is decreased by the loss of 

 fluid and the blood-pressure is lowered. The distribution of blood 

 is materially changed and the body temperature is lowered. While 

 the intestinal mucous membrane and the other abdominal organs 

 are rich in blood, especially after the administration of drastics, 

 the more distant organs, as the brain, lungs and skin, are corre- 

 spondingly poor in blood, the blood being diverted from the latter 

 to the intestines. The activity of the kidneys is at first increased 

 by some cathartics; for example, diuresis is increased a few hours 



