254 ANIMAL BIOLOGY 



disorders. When we eat too much, consider what must 

 happen. The digestive organs are overstimulated in the 

 effort to dispose of the extra food. Constipation fre- 

 quently follows. Materials which should have been got 

 rid of undergo decomposition, producing injurious sub- 

 stances that are absorbed by the blood and poison the 

 whole body. Excess of food commonly leads also to the 

 torpidity of the liver. One of the functions of this much 

 abused organ is the breaking up of various products 

 resulting from the metabolism of the tissues. If the liver 

 is sluggish, injurious substances may accumulate in the 

 blood and produce very disagreeable feelings. Practically 

 all of the carbohydrates that are absorbed from the 

 stomach and intestines pass through the liver cells. Many 

 people who eat too much rich candy or other sweets at all 

 sorts of unseasonable times, and suffer from headache 

 and general lassitude as a result, are apparently unaware 

 that they bring these unpleasant consequences on them- 

 selves, by imposing upon the poor liver greater burdens 

 than it can well endure. 



The welfare of the liver is of especial value for the main- 

 tenance of health, because this organ performs so many 

 indispensable functions. It destroys poisonous substances 

 in the blood by converting them into less injurious mate- 

 rials. It eliminates various materials which are discharged 

 through the bile duct into the intestine, while it secretes 

 other substances whose presence in the intestine facilitates 

 the absorption of food and checks the undue decomposition 

 of waste matter. It also acts on dextrose (the substance 

 into which carbohydrates are converted when they are 

 absorbed into the blood), converting it into glycogen. 

 There are other functions ascribed to the liver but these 

 are the best known. The ills that arise from the mal- 

 treatment of the liver are numerous, and in many cases 



