THE SEAT OF FORMATION OF UREA 685 



Sjoquist method, and similar results obtained. The urine 

 remained strongly acid to the end, although a very large dose 

 of alkali, 10 grm. of sodium carbonate, had been introduced 

 into the stomach before the operation. At the post-mortem 

 examination it was found that 28 grm. of liver, or 5'4 per cent, 

 of the intact organ, had not been included in the ligatures, and 

 was still in connection with the circulation. The peritoneal 

 cavity contained 500 c.c. of blood. The ammonia content of 

 the blood, brain, and muscles was estimated and found to be 

 within the normal, but in some other experiments it was found 

 to be moderately increased. In none of the experiments was 

 the removal of the liver complete, and never less than about 

 5 per cent, of the organ was unligatured. 



These experiments show that for a few hours after the 

 removal of the bulk of the liver the urine still contains large 

 quantities of urea ; that the percentage of N excreted as urea 

 is decreased, and that the percentage excreted as ammonia 

 is increased, but not quite correspondingly to the decrease as 

 urea. These facts are clearly open to more than one inter- 

 pretation. They might be explained by saying that after 

 the removal of the liver urea is still produced by some organ 

 other than the liver from some substance other than ammonia. 

 But these experiments cannot be held to prove it. For, not 

 only was an appreciable amount of liver still connected with 

 the circulation, but there is nothing to show that urea was 

 produced after the operation, and that the urea excreted was 

 not already preformed in the body. Even if urea had been 

 formed after the operation it might still have arisen from 

 arginin. Again, the experiments might be considered to show 

 that ammonium salts are the chief immediate precursors of 

 urea, and, as we have seen, are converted into urea solely in 

 the liver ; in fact, the results might appear to be very similar 

 to those obtained when a dog with an Eck's fistula receives a 

 meal of proteids. For in both cases the dogs became convulsed, 

 and the urine is found to contain more ammonia relatively 

 to the urea. But, as Salaskin and Zaleski pointed out, the 

 resemblance is merely superficial and the two conditions are 

 fundamentally different. In these experiments the convulsions 

 could not be due to ammonia poisoning, for in some of them 

 the percentage of ammonia in the blood and brain remained 



