464 VICTOR C. MYERS 



the liver depends essentially upon the food intake. In starvation the gly- 

 cogen may almost disappear from the liver, but after food very rich in 

 carbohydrate it may in exceptional cases reach nearly 20 per cent. Ap- 

 parently only the fermentible sugars of the six carbon series or their di- 

 and polysaccharids are true glycogenformers. The di- and poly saccha rids 

 must, however, first be broken down into monosaccharids in digestion. 

 Glucose is apparently more readily converted into glycogen than fructose, 

 and much more readily than galactose. These transformations are ap- 

 parently brought about by the diastatic ferment of the liver. The liver 

 is the probable source of the blood diastase. It is of interest that in dia- 

 betes, where the reserve supply of glycogen in the liver is very small, the 

 diastatic activity of the blood is generally markedly increased. It is 

 further significant that when the liver is cut out of the circulation in 

 animals, the blood sugar rapidly falls and may almost disappear. The in- 

 fluence of the- various internal secretions and also Bernard's sugar puncture 

 are of considerable interest and importance in this connection. As regards 

 the formation of sugar from protein it would seem probable that the liver 

 was chiefly concerned in the deamidization of amino-acids and the trans- 

 formation of the carbon moiety to sugar. Not all amino-acids are sugar- 

 formers, although it may be noted that practically all the amino-acids with 

 straight chains, except lysin, yield sugar. Prolin is the only cyclic amino- 

 acid which produces an abundance of sugar. 



That urea formation, takes place in the liver is unquestioned as a 

 result of the well-known experiments of von Schroeder and others. That 

 the liver is the only organ in the body where urea formation takes place 

 seems improbable, still the actual demonstration of the formation of urea 

 elsewhere than in the liver has not been made. In autolysis experiments 

 M. Ringer was able to demonstrate urea formation in liver tissue but 

 not in muscle tissue. Muscle tissue added to liver tissue was found, how- 

 ever, to augment the urea formation. It would appear that the liver was 

 the chief organ concerned in the synthesis of urea, apparently deamidizing 

 the amino-acids no longer of use to the body or in excess of the body's 

 requirements. In the case of the amino-acid, arginin, Kossel and Dakin 

 have shown that a specific liver enzyme, arginase, converts the arginin 

 to ornithin and urea. 



The liver has its own secretion, bile, which it continuously secretes ; a 

 reservoir, the gall bladder, being provided, so that the bile need not be 

 discharged into the intestine except as required. The discharge of bile is 

 brought about by the same stimulus that initiates the secretion of pan- 

 creatic juice, namely secretin. Bile may be regarded not only as a 

 secretion but also as an excretion, since it carries to the intestine certain 

 metals, cholesterol, lecithin, decomposition products of hemoglobin, and 

 certain foreign organic substances, for example, tetrachlorphthalein. 



In man bile is usually a golden yellow, rather viscid fluid, amounting 



