728 URINE. 



the cells of the digestive glands, the stomach, the pancreas, and the in- 

 testinal mucosa (of dogs) as the time when protein foods are being digested 

 and transported to the liver. As the ammonia introduced into the liver 

 is transformed into urea (see above), we can therefore expect that in 

 certain diseases of the liver an increased elimination of ammonia and a 

 decreased excretion of urea will occur. In how far this is true has already 

 been stated (page 651), and we refer to the researches of the various 

 authors there cited. 



In man and certain animals the elimination of ammonia is increased 

 by the introduction of mineral acids; and, as shown by JoLiN, 1 organic 

 acids, such as benzoic acid, which are not destroyed in the body act in a 

 similar manner. The ammonia set free in the protein destruction is in 

 part used in the neutralization of the acids introduced, and in this way 

 a destructive removal of fixed alkalies is prevented. This dissimilar 

 tendency of different animals toward acidosis has been discussed in the 

 previous pages. 



Acids formed in the destruction of proteins in the body act on the 

 elimination of ammonia like those introduced from without. For this 

 reason the quantity of ammonia in human urine is increased under such 

 conditions and in such diseases where an increased formation of acid 

 takes place because of an increased metabolism of proteins. This is the 

 case with a lack of oxygen in fevers and diabetes. In the last-mentioned 

 disease, organic acids ^-oxybutyric acid and acetoacetic acid are pro- 

 duced, which pass into the urine combined with ammonia. 2 Other 

 observations also indicate that the elimination of ammonia by the urine 

 is increased on insufficient or diminished supply of alkalies or alkaline 

 earths. 



The detection and quantitative estimation of ammonia used to be performed 

 according to the method suggested by SCHLOSING. The principle of this method 

 is that the ammonia from a measured amount of urine is set free by lime-water 

 in a closed vessel and absorbed by a measured amount of N/10 sulphuric acid. 

 After the absorption of the ammonia the quantity is determined by titrating the 

 remaining free sulphuric acid with a N/10 caustic-alkali solution. This method 

 gives low results, and in exact work we must proceed as suggested by BORLAND.* 



The recent methods for estimating the ammonia are all based upon 

 the distillation of the ammonia, after the addition of lime, magnesia, 

 or alkali carbonate, at low temperatures either by the aid of vacuum 

 (NENCKI and ZALESKI, WURSTER, KRUGER, REICH and SCHITTENHELM, 



1 Jolin, Skand. Arch. f. Physiol., 1. In regard to the behavior of ammonium salts 

 in the animal body, see Rumpf and Kleine, Zeitschr. f. Biologic, 34; Kowalcwski and 

 Markewicz, Bioch. Zeitschr., 4, and the works cited on page 641. 



2 On the elimination of ammonia in disease, see the works of Rumpf, Virchow's 

 Arch., 143; Hallervorden, ibid. 



3 Pfluger's Arch., 43, 32. 



