8 QUATERCENTENARY STUDIES IN PATHOLOGY 



Ammonium carbamate when dissolved in water will decompose until 

 there is in the solution exactly the same amount of ammonium 

 carbamate as if an equivalent amount of ammonium carbonate had been 

 dissolved. 



Consequently, as in the above experiments, when carbamate is 

 injected intravenously, or when it is given by the stomach, it must have 

 largely decomposed before gaining the blood. If carbamate is produced 

 in the intestines after flesh has been ingested it will be largely converted 

 into ammonium carbonate before getting far in the blood. In other 

 words ammonium ions will have been produced from it. 



Pawlow and Nencki did consider this probability, but thought that the 

 symptoms produced by injection of carbamate-free ammonium salts were 

 distinctly different from those which follow carbamate injection. Their 

 comparison of the two {i.e., ammonium and carbamate), however, was 

 concerned only with the general symptoms, and these, being entirely 

 objective, are necessarily difficult to compare. I have found that the 

 effect on the mean arterial blood pressure and respirations of solutions 

 of ammonium carbamate and ammonium bicarbonate are identical in 

 every respect. Now, one of these will contain much more carbamate 

 than the other, the bicarbonate containing only a small amount of 

 carbamate, so that on the blood pressure at least the effect can be entirely 

 ascribed to the ammonium ion. 



We see then that the main question regarding these symptoms 

 concerns not so much the presence of excess of carbamic acid in the 

 organism as the presence of an excess of ammonia. Even if the 

 symptoms are due to carbamate intoxication there must be excess of 

 ammonia. In their more recent publications the St. Petersburg workers 

 have accordingly confined their attention to the behaviour of the 

 ammonia content of the organism in Eck's fistula dogs. At the outset, in 

 doing this, it soon became evident that exact information regarding the 

 quantitative distribution and the source of ammonia in the normal 2x\\^2\ 

 body had first of all to be obtained. 



Nencki, Pawlow and Zaleski (9) and later Salaskin (^o), by the use of 

 accurate methods for the determination of ammonia in the blood and the 

 various organs, have recently furnished this information. The following 

 are among their main conclusions. 



(272) 



