50 HUMAN PHYSIOLOGY 



will be presently described. The result is an excess 

 of sugar-supply inducing a much enfeebled condition 

 of body, associated with kidney-trouble, represented 

 by a very much increased flow of urine. The origin 

 of this disease is still undetermined, but it would 

 appear to arise from some defect in the working of 

 the nervous system taking the shape of a lack of 

 control over the liver and its sugar-producing 

 functions ; a duty carried out by some nerve centre 

 specially devoted to the regulation of the function in 

 question. 



THE BILE. Bile is to be regarded as waste 

 matter which the cells of the liver have separated 

 from the blood. The liver may thus be ranked with 

 the skin, lungs, and kidneys, as an organ which tends 

 to deal with a certain proportion of the waste which 

 is inseparable from the wear and tear of life. Bile 

 is a dark greenish-coloured fluid of a complicated 

 character. It is, as we have seen, a waste product 

 made useful. Poured on the food, it exerts a special 

 digestive action on the fats of the food, breaking 

 down the globules of the fat, emulsifying them and 

 thus rendering them more readily incorporated with 

 other foods and also more readily absorbed. Bile 

 also exercises on the food a certain antiseptic action 

 preventing the food in the intestine from undergoing 

 injurious changes, whilst a third function, that of 

 stimulating the movements of the intestine, may be 

 attributed to it. We see a lack of this stimulating 

 action, when, on account of the deficiency of bile, 

 constipation becomes a marked symptom amongst 

 other signs of digestive irregularity. 



THE SWEETBREAD. The sweetbread or pancreas 

 lies below and in front of the stomach. It is an 

 organ in shape somewhat resembling a dog's tongue, 



