METABOLISM. 47<) 



ill iu by the mouth in man increases the excretion of uric acid. The 

 purin bases are present in beer and porter, coming from the nuclein of 

 the yeast. Alcohol has no striking action upon the excretion of uric 

 acid. Salicylic acid has a decided increased action on the output of 

 uric acid. 



The different tissues contain a uricolytic ferment which breaks up 

 uric acid into urea and other bodies. The liver seems to be the 

 principal seat for the destruction of uric acid. In diabetes there is an 

 inability of the tissues to destroy sugar; in gout the symptoms are 

 dependent upon the deposit of acid urate of sodium in certain localities. 



Metabolism of Carbohydrates. 



When carbohydrates enter the tissues they may (1) undergo 

 combustion, (2) may be stored up as glycogen or fat, or (3) being only 

 partly consumed they may be excreted in the urine. 



Nencki has shown that 10 per cent, glucose when mixed with 20 

 per cent, of caustic alkali at the temperature of the body, at the end 

 of twenty-four hours contains only traces of sugar, but lactic acid 

 amounting to 50 per cent, of the sugar taken. Bacteria change grape 

 sugar into 80 per cent, of lactic acid. Buchner believes that the first 

 stage in the alcoholic fermentation of sugar is due to zymase changing 

 sugar into lactic acid, and lactacidase, a second ferment of the yeast 

 cell, converting the lactic acid into alcohol. 



Asher arid Jackson removed all the abdominal viscera in a dog 

 and they found that the lactic acid in the blood was increased. 

 Minkowski extirpated the liver in geese, and here lactic acid and 

 ammonia replaced the uric acid in the urine. 



Proteids in breaking up into the amino-acids form one, alanine, 

 which may be a small source of lactic acid. We know that in muscle 

 activity sarco-lactic acid is formed. 



Alanine when given to rabbits, causes glycogen to be deposited in 

 the liver and the excretion of lactic acid by the kidneys. The 

 glycerine in the body can produce sugar. The nucleo-proteids also 

 have a carbohydrate or pentose, and the gluco-proteids contain gluco- 

 samine, but how far they are concerned in metabolism is still a matter 

 of obscurity. 



In certain families a pentosuria exists, a carbohydrate of the five 

 carbon series, a pentose is excreted. The sugar excreted is the optically 

 inactive racemic, arabinose. It arises within the organism itself. 

 This diabetes needs no dieting. 



Sugar may become oxidized in the body without previous splitting, 



