60 CROONIAN LECTURES 



of the problem why a portion of the albuminous 

 food passes off as urates in the urine, whilst the 

 larger portion remains as albumen in the blood. 



Kiihne shows that albuminous and fibrinous 

 substances when subjected to the continuous 

 action of the pancreatic juice give rise to 

 tyrosine, leucine, and an aniline-like substance 

 in much greater quantity than happens when 

 albumen is fused with potassa, or boiled with 

 sulphuric acid, or allowed to decompose. 



Here are tyrosine and leucine thus prepared 

 by the action of the pancreatic juice. 



It seems in the highest degree probable 

 that, when an excess of albuminous food is 

 taken, then, in consequence of the slower 

 absorption, a portion of it remains long exposed 

 to the action of the pancreatic fluid, and this 

 continued action of the pancreatic fluid on 

 albumen produces substances which are able, 

 more or less immediately, to form uric acid. 



The relation of some of these substances is 

 seen in the following table : 



Tyrosine = C 9 H 11 N O 3 



Leucine = C 6 H 13 N O 2 



Uric acid = C 5 H 4 N 4 O 3 



Creatine = O 4 H 9 N 3 2 ' 



Urea = C H 4 N 2 O 



