INTERNAL SECRETIONS 153 



If the liver is isolated from the circulation -by joining the 

 portal vein directly with the inferior vena cava, the urine 

 excreted contains less urea and more ammonium salts than 

 normally and the animal shows symptoms of poisoning 

 characteristic of the ammonium compounds. Extirpation 

 of the liver in birds is followed by the appearance of 

 ammonia and lactic acid in the urine instead of uric acid. 



The object of this change which the ammonia salts 

 undergo in the liver seems to be to change the poisonous 

 ammonia into harmless substance. 



The liver, inserted as a filter between the capillary network of 

 the portal vein, acts upon the substances absorbed from the intes- 

 tine. In the first place, it changes the injurious products of 

 proteid putrefaction, phenol, skatol, indol, into the harmless 

 ethereal sulphates which are excreted in the form of alkali salts. 

 In the second place, the liver retains the vegetable and animal 

 poisons (alkaloids) incidentally introduced into the alimentary 

 canal ; these poisons are destroyed and excreted with the bile. In 

 the third place, metallic poisons (arsenic, antimony, lead) are 

 deposited in the liver and the body is thus shielded from their 

 injurious effect. These poisons are also finally excreted. 



The anatomical relation between the spleen and the liver (the 

 splenic vein is a branch of the portal vein) points to a physiological 

 relation between these two organs. Perhaps the hoemoglobin set 

 free in the spleen by the breaking down of the red blood corpus- 

 cles is decomposed in the liver. 



In the rabbit many lobes of the liver can be removed without 

 any disturbance being noticed. The extirpated lobes are soon 

 replaced. 



IV. The pancreas. Besides the secreting of pancreatic 

 juice, the pancreas plays an important part in the metabolism 

 of carbohydrates. After extirpation of the pancreas the 

 carbohydrates are no longer properly oxidized in the body 

 and hence are largely excreted with the urine (pancreatic 

 diabetes). If a small part of the pancreas is left, no diabetes 

 results. On the other hand, injection of pancreatic juice or 

 feeding with pancreas does not stop the diabetes, but in- 

 creases it. Extirpation of the pancreas causes the liver to 

 lose its power of forming glycogen, and the tissues their 

 power of oxidizing sugar. 



