10 QUATERCENTENARY STUDIES IN PATHOLOGY 



the brain. When a certain amount of ammonia has accumulated in the 

 brain, symptoms appear, and if the dog recover from these and receive 

 no more strongly nitrogenous food for some time, this excess of ammonia 

 in the brain will gradually be carried away in the blood again, and either 

 become converted into urea or escape into the urine. It will be evident 

 from the above that there may or may not be excess of ammonia in the 

 blood and urine when symptoms are present. 



To induce the above symptoms more acutely, Nencki and Pawlow 

 ("), after making an Eck's fistula in a dog, removed as much (5/6 

 to 7/8) of the liver as possible. The dogs lived on an average from 

 two to three hours after the operation. One of the animals 

 remained in a comatose state after the removal. One dog, however, so 

 far recovered as to run about for some time, but soon showed tetanic 

 convulsions ending in death. The symptoms were not strictly like those 

 portrayed above. In two of these dogs the ammonia in the blood and 

 urine was found to be increased. The urea in the urine was diminished, 

 whereas the urea in the blood remained normal in amount. This last result 

 is due to the fact that urea formation is not confined to the liver but may 

 occur elsewhere in the organism. The increase of ammonia in the blood 

 was not great enough to account for death. It was consequently thought 

 that perhaps some toxic substances had been produced by the removal 

 of the liver. No experimental evidence of this could, however, be 

 obtained by inoculating a normal rabbit with some of the urine excreted 

 by the dogs. 



In other dogs with Eck's fistula instead of removing the liver, the 

 hepatic artery was ligated. Some of these dogs lived 12 to 15 hours, 

 apparently recovering well from the operation, but afterwards passing into 

 a comatose condition. In one of these dogs, the blood was examined 

 chemically. For about seven hours after the operation this dog did not 

 show anything abnormal, but then clonic convulsions appeared, passing 

 into coma, and ending in death (8J hours after operation). 



The ammonia content of the blood was found to be unaffected by 

 this operation, so that death must have been due to some cause other 

 than ammonia intoxication. 



These observations recall others by Lieblein (^^) in which the liver 

 cells were destroyed by injecting acid into the hepatic ducts. The dogs 

 became comatous, and died much in the same way as after removal of the 



(274) 



