72 SCIENCE PROGRESS. 



changes a proteid seems to undergo within the tissue cells 

 result in the formation of ammonia, not of urea. This ammonia 

 passing into the lymph and blood combines with carbonic 

 acid to form either carbamic acid or carbonate of ammonium. 

 The production of carbamic acid especially occurs if the 

 fluid is alkaline. Drechsel 1 has found it in the blood-serum, 

 and Drechsel and Abel 2 have found it in horses' urine. 



Schroder's experiments have shown that ammonium 

 carbonate added to blood circulating artificially through 

 an isolated liver, is directly converted into urea. This 

 is confirmed, and the view that this is the normal method 

 within the body is upheld by the experiments in which the 

 urea and ammonium salts have been quantitatively determined 

 in the urine. When a strong mineral acid is administered 

 so as to render the blood plasma less alkaline, more and 

 more of the eliminated nitrogen appears as the ammonium 

 salt of a mineral acid (sulphate, chloride, etc.), and less as 

 urea. And we know, further, that ammonia presented to 

 the liver cells, in combination with strong mineral acids, is 

 not altered by them. 



The changes occurring, then, to proteids within the 

 body are first hydrolisation, and then the carbon is split 

 off, atom by atom, and burnt to form carbonic anhydride. 

 That this gradual disintegration is possible is shown by 

 a previous research of Drechsel's 3 relating to the action 

 of strong alternating currents upon caproic acid. The 

 alternating current acts upon the solution so as to produce 

 rapidly changing series of oxidations and reductions. By 

 an examination of the results Drechsel found that from 

 the caproic CH 3 .(CH 2 ) + CO.OH, oxy-caproic CH,.OH. 

 (CH 2 ) 4 CO.OH acid arose by oxidation, from this adipic 

 acid CO.OH(CH 2 ) 4 CO.OH arises by oxidation, and on 

 oxidation of this oxy-valerianic acid CH 2 OH(CH 2 ) 3 CO.OH 

 and carbonic anhydride are produced, and so on till all the 

 carbon atoms are burnt off as carbonic anhydride. 



Again, from oxy-valerianic acid CH 2 OH.(CH 2 ) 3 CO.OH 



1 Sitz. der Konigl. Sticks Gesell. Sitzung vom., 21 April, 1875. 



2 Du Bois Archiv, p. 236, 1891. 



3 Journ. Prak. Chemie (2), vol. 34, p. 135. 



