652 URINE. 



which, irrespective of the pronounced atrophy, an abundant formation 

 of urea occurs, and no appreciable, if any, change in the proportion of 

 ammonia to the total nitrogen and urea is observed. After shutting 

 out from the circulation the organs of the posterior part of the body, 

 especially the liver and kidneys, KAUFMANN 1 also found an important 

 increase in the urea of the blood, and these different observations show 

 that the liver is not the only organ, in the various animals experimented 

 upon, in which urea is formed. 



The observations made by numerous investigators 2 on human beings 

 with cirrhosis of the liver, acute yellow atrophy of the liver, and phos- 

 phorus poisoning have led to the same result. These investigations 

 teach that in certain cases the proportion of the nitrogenous substances 

 may be so changed that urea is only 50-60 per cent of the total nitrogen, 

 while in other cases, on the contrary, even in very extensive atrophy 

 of the liver-cells, the formation of urea is not diminished, neither is the 

 proportion between the total nitrogen, urea, and ammonia essentially 

 changed. Even in the cases in which the formation of urea was relatively 

 diminished and the elimination of ammonia considerably increased, fur- 

 ther investigation must be instituted before it will be possible to assume 

 a reduced ability of the organism to produce urea. An increased elimina- 

 tion of ammonia may, as shown by MUNZER in the case of acute phos- 

 phorus poisoning, be dependent upon the formation of abnormally large 

 quantities of acids, caused by abnormal metabolism, and these acids 

 require a greater quantity of ammonia for their neutralization accord- 

 ing to the law of elimination of ammonia, which will be given later. 

 That an abnormal formation of acid occurs after the cutting out of the 

 liver has been especially shown by SALASKIN and ZALESKI. S 



For the present we are not justified in the statement that the liver 

 is the only organ in which urea is formed, and only continued investiga- 

 tion can yield further information as to the extent and importance of the 

 formation of urea, from ammonium compounds, in the liver. 



Properties and Reactions of Urea. Urea crystallizes in needles or in 

 long, colorless, four-sided, often hollow, anhydrous rhombic prisms. It 

 has a neutral reaction, and produces a cooling sensation on the tongue 

 like saltpeter. It melts at 132 C. At ordinary temperatures it dissolves 



1 Compt. rend. soc. biol., 46, and Arch, de Physiol., (5), 6. 



2 See Hallervorden, Arch. f. exp. Path. u. Pharm., 12; Weintraud, ibid., 31; Munzer 

 and Winterberg, ibid., 33; Stadelmann, Deutsch. Arch. f. klin. Med., 33; Fawitzki, 

 ibid., 45; Munzer, ibid., 52; Frankel, Berlin, klin. Wochenschr., 1878; Richter, ibid., 

 1896; Morner and Sjoqvist, Skand. Arch. f. Fhysiol., 2, and Sjoqvist, Nord. Med. 

 Arkiv, 1892; Gumlich, Zeitschr. f. physiol. Chem., 17; v. Noorden, Lehrb. d. Pathol. 

 des Stoffwechsels, 2. Aufl., Bd. 1, 104. 



3 Zeitschr. f. physiol. Chem., 29. 



