382 CONSTIPATION AND DIARRHCEA. 



sulphates. While the alkaloids, morphia, strychnia, digitalin, narcotin, veratria 

 have a similar action ; quinine favours it (Wolberg). In some nervous individuals 

 a " peristaltic un-rest of the stomach," conjoined with a dyspeptic condition, occurs 

 (Kussmaul). 



E. In acute diseases, the secretion of bile is affected ; it becomes less in amount 

 and more watery, i.e., it contains less specific constituents. If the liver undergoes 

 great structural change, the secretion may be arrested. 



F. Gallstones. When decomposition of the bile occurs, gallstones are formed 

 in the gall-bladder or in the bile-ducts. Some are white, and consist almost entirely 

 of stratified layers of crystals of cholesterin. The brown forms consist of bilirubin- 

 lime and calcium carbonate, often mixed with iron, copper, and manganese. The 

 gallstones in the gall-bladder become facetted by rubbing against each other. The 

 nucleus of the white stones often consists of chalk and bile colouring matters, 

 together with nitrogenous residues, derived from shed epithelium, mucin, bile salts 

 and fats. Gallstones may occlude the bile-duct and cause chola3mia. When a 

 small stone becomes impacted in a duct, it gives rise to excessive pain constituting 

 hepatic colic, and may even cause rupture of the bile-duct with its sharp edges. 



G. Nothing certain has been determined regarding the pancreatic secretion 

 in disease, but in fever, it appears to be diminished in amount and digestive 

 activity. The suppression of the pancreatic secretion [as by a cancerous tumour 

 of the head of the pancreas] is often accompanied by the appearance of fat in the 

 form of globules or groups of crystals in the faeces. 



H. Constipation is a most important derangement of the digestive tract. It 

 may be caused by 1. Conditions which obstruct the normal channel, e.g., con- 

 striction of the gut from stricture in the large gut after dysentery, tumours, 

 rotation on its axis of a loop of intestine (volvulus), or invagination, occlusion 

 of a coil of gut in a hernial sac, or by the pressure of tumours or exudations 

 from without, or congenital absence of the anus. 2. Too great dryness of 

 the contents, caused by too little water in the articles of diet, diminution 

 of the amount of the digestive secretions, e.g., of bile in icterus; or in 

 consequence of much fluid being given off by other organs, as after copious 

 secretion of saliva, milk, or in fever. 3. Variations in the functional activity of 

 the muscles and motor-nervous apparatus of the gut may cause constipation, owing 

 to imperfect peristalsis. This condition occurs in inflammations, degenerations, 

 chronic catarrh, diaphragmatic inflammation. Affections of the spinal cord, and 

 sometimes also of the brain, are usually accompanied by slow evacuation of the 

 intestine. Whether diminished mental activity and hypochondrias are the cause 

 of or are caused by constipation is not proved. Spasmodic contraction of a part of 

 the intestine may cause temporary retention of the intestinal contents, and, at the 

 same time, give rise to great pain or colic ; the same is true of spasm of the anal 

 sphincter, which may be excited reflexly from the lower part of the gut. The 

 faecal masses in constipation are usually hard and dry, owing to the water being 

 absorbed ; hence they form large masses or scybala within the large intestine, and 

 these again give rise to new resistance. 



Amongst the reagents which prevent evacuation of the bowels, some paralyse the 

 motor apparatus temporarily, e.g., opium, morphia; some diminish the secretion of 

 the intestinal mucous membrane, and cause constriction of the blood-vessels, as 

 tannic acid, vegetables containing tannin, alum, chalk, lead acetate, silver nitrate, 

 bismuth nitrate. 



I. Increased evacuation of the intestinal contents is usually accompanied by a 

 watery condition of the faeces, constituting diarrhoea. 



The causes are : 



1. A too rapid movement of the contents through the intestine, chiefly through 

 the large intestine, so that there is not time for the normal amount of absorption 

 to take place. The increased peristalsis depends upon stimulation of the motor- 



