THE METABOLISM OF PBOI 617 



vomiting of pregnancy, for example, a relatively high excretion of am- 

 monia lias been found associated with no greater a def if acidosis, as 

 determined by the power of the plasma to absorb carbonic acid, than in 

 normal cases of pregnancy. 



Influence of Liver on Ammonia-Urea Ratio. — Experimental Observa- 

 tions: (1) Removal of Ltveb. — There are several facts which indicate that 

 other causes than acid-production may interfere with the conversion of am- 

 monia into urea. What are these causes) Su 

 the liver is the organ which mosl actively converts amino 

 into area, it would be natural to expect, that, when the functions of 

 this organ were interfered with, relatively more of the nitrogen 

 tion would occur as ammonia and relatively less - area. Tn order to 

 determine the exact significance of the liver as a area-forming organ, 

 two types of in tion have been used; namely, (1) observation of 



the changes produced in the ammonia-urea ratio in the urine by partial 

 or total removal of tho liver: and (2) observation of the urea-forming 

 power of a liver perfused outside the body. 



To remove the liver from the circulation the portal vein is brought 

 in apposition with the vena cava, the two are sewed together, and a 

 passage opened between them, after which the portal vein is ligated al 

 the anastomosis (forming the so-called Eck fistula). The portal hi 

 then passes directly into the vena cava, and the liver is now supplied 

 only by the hepatic artery. The animals live for a considerable time 

 after the operation, and the urini intly contains relatively 



urea and more ammonia than normal. The results are. however, not 

 nearly iking as would be expected if the liver were the main - 



of urea formation. The experiments have nevertheless brought to 1:_ 

 a fact of considerable clinical interest- namely, although the animals 

 may thrive if kept on a diet nol containing an they im- 



mediately begin to develop peculiar symptoms, not unlike those of 

 lampsia or uremia, when they are fed with large amounts of flea! 

 Mosl of the symptoms can ! erred to abnormal stimulation of the 



central nervous system, and examination of the urine has shown a 1. 

 increase in the excretion of ammonia and a change from the norma! 

 acid reaction to an alkaline 



At one time it was assumed thai the toxic symptoms were caused by 

 the presence in the blood of ammonium carbamate, since large quantities 

 of the calcium salt of this substance could he separati urine. 



It is now known, however, that the ammonium carbamate t only 



use of tl Mim carbonate, the two ^-.hs existing I 



gether in solution according tn the lav tion. That the in' 



ication is not due to ammonium carbamate d< seclude tl 



