THE CHEMISTEY OF THE LIVER 645 



instead, which results in a marked increase of acetoacetic acid. The role 

 of the liver in the production of acetone bodies is also well illustrated: 

 by the work of Fischler and Kossow, who studied the effect of the com- 

 bined action of hunger and phlorhizin on Eck fistula and "reversed" Eck 

 fistula dogs. (The "reversed" Eck fistula is made by ligating the inferior 

 vena cava just above its anastomosis with the portal vein. The blood of the 

 lower extremities and of the abdominal viscera is thus diverted into the 

 portal vein and made to circulate through the liver and this, according to 

 Fischler, greatly stimulates the functional activity of this organ.) It was 

 observed that under these conditions the Eck fistula dogs excrete a small 

 quantity of acetone bodies, the normal dogs excrete a larger quantity, and 

 the reversed Eck fistula dogs excrete the greatest amount. 



The Liver and Proteins. From 10 to 25 per cent of the total nitrogen 

 of the liver is in the form of connective tissue; from 45 to 65 per cent 

 is contained in the albumin and hemoglobin fractions ; and from 25 to 30 

 per cent is in the globulin fraction. During autolysis, the last fraction 

 is digested, exclusively (Bradley). 



The liver takes an active part in the deaminization of amino acids that 

 result from the enzymatic cleavage of protein in the small intestine; it is 

 also concerned with the conversion of the liberated ammonia into urea and 

 with the further oxidation of the deaminized acids. The amino acids 

 leucin, tyrosin, phenylalanin (Embden and his pupils), histidin (Dakin 

 and Wakeman) and tryptophan (Homer), are oxidized to acetoacetic acid, 

 when perfused through the surviving liver. The bulk of the carbon of the 

 amino acids is synthesized into glucose and it is probable that the liver 

 is chiefly concerned with this process. That the liver can synthesize urea 

 from ammonia is now admitted by all investigators. Normally, basic 

 ammonia is converted into neutral urea, but when necessary, part of it 

 may be diverted to neutralize acetoacetic, betahydroxybutyric or other 

 acids. The importance of this activity in the regulation of the acid-base 

 equilibrium is clear. 



The following experiments illustrate the importance of the liver in 

 protein metabolism. Fischler observed that when Eck fistula dogs were 

 fed with large quantities of meat they developed poisonous symptoms such 

 as ataxia, catalepsy, amaurosis, coma and convulsions coincident with the 

 secretion of an alkaline urine and saliva. These symptoms could be pre- 

 vented by 1 The- Administration of phosphoric acid. Fischler ascribes this 

 condition to an alkalosis which results from the incomplete conversion of 

 ammonia into urea. The same author noted that when Eck fistula dogs 

 were starved and then injected with phlorhizin they also developed coma 

 and convulsions, but now the ammonia and urea excretion was decreased. 

 These symptoms are ascribed to toxic substances which result from the 

 imperfect oxidation of amino acids. 



Van Slyke and Meyer (c) have shown that after amino acids are in- 



