THE LARGE INTESTINE 405 



and absorbed by the small intestine. No large excess of digestible 

 foodstuffs should be passed, with the juices capable of digesting them, 

 into the large intestine, for the products of digestion cannot be, or 

 are not readily, absorbed there. More important still, the movements 

 of the large intestine must be aided by the massage obtained by exercise 

 of the abdominal muscles, by hard physical work, and deep breathing. 

 The great prevalence of trouble in the large intestine is due to loading 

 it with excess food, and to the development of a sluggish colon 

 by lack of exercise. Plain living and exercise, not the quack's pill 

 or the surgeon's knife, are the cure for the troubles which arise in 

 this region of the gut. The fortunes of pill-vendors are an index of 

 the gluttony and sloth of man. 

 Faeces. The faeces consist of 



1. Indigestible material, such as keratin and cellulose. 



2. Material digested with difficulty elastin, cartilage. 



3. Superfluous and non-absorbed products of digestion fatty 

 acids, insoluble soaps, amino-acids, purin bodies from nucleo-protein, 

 haematin from haemoglobin, toxic bodies with an aronlatic nucleus. 



4. Products of bacterial activity indol, skatol. These are ab- 

 sorbed and excreted in the urine as non-toxic compounds of sulphuric 

 and glycuronic acids. 



5. Components of digestive juices secreted by the alimentary tract 

 trypsin, diastase, cholalic acid, bile salts, lecithin, stercobilin from 

 bile pigments, coprosterin from cholesterin. 



- 6. Excretion of the intestinal wall calcium and iron salts, epithelial 

 cells, leucocytes. 



7. Bacteria, forming a large part of the faeces, even half the weight. 



The faeces are as a rule alkaline or neutral in reaction. The bulk 

 varies with the kind of food and kind of animal. In man, on a mixed 

 diet, the daily amount evacuated is about 1-20 to 150 grains, containing 

 30 to 37 grains of solids ; on a vegetable diet, 333 grains, and 75 grains 

 of solids. The offensive smell is mostly due to skatol. The colour 

 varies according to the food. Meat gives a dark, almost black, stool; 

 large amounts of fat make the faeces clay-coloured; much bread im- 

 parts a light colour. The breast-fed infant passes motions of the 

 colour and consistency of mustard, acid in reaction, and inoffensive in 

 smell. Meconium, the dark-greenish faeces passed by the newly-born 

 child, are similarly acid in reaction, and inoffensive. It consists of 

 cells, and remains of bile and digestive fluids. There is no sign of 

 any bacterial action. 



The chemical analysis of the faeces is not often undertaken in 

 clinical laboratories. It affords valuable information in certain 

 conditions . 



