390 THE LIVER. 



The action of monamino-acids upon the carbohydrate metabolism 

 has also given important ground for the assumption of a sugar forma- 

 tion from protein. That a deamidation occurs in the animal body was 

 shown by the earlier observations of BAUMANN and BLENDERMANN. 

 Further proofs of this were furnished by the recent investigations of 

 NEUBERG and LANGSTEIN, where in feeding experiments with alanine 

 they found abundance of lactic acid in urine, and P. MAYER observed 

 gly eerie acid in the urine after the subcutaneous injection of diamino- 

 propionic acid. Finally, LANG 1 has shown that various organs in anti- 

 septic autolysis have the power of deamidizing amides and amino-acids. 

 As from amino-acids by deamidation it is possible to produce oxyfatty 

 acids according to the formula CH.NH 2 + H 2 O = CH(OH)+NH X , 

 it was interesting to test the action of amino-acids upon carbohydrate 

 metabolism. Several investigations have been carried on with this in 

 view, such as those of LANGSTEIN and NEUBERG, R. COHN and F. KRAUS, 

 which have shown a very probable formation of carbohydrate under the 

 influence of amino-acids; but the investigations of EMBDEN and SALOMON 

 and of EMBDEN and ALMAGIA have positively shown, in a dog without 

 a pancreas, that the amino-acids can bring about a re-formation of car- 

 bohydrate. LUSK 2 has shown the same with glutamic acid when fed 

 to dogs poisoned with phlorhizin. It is still an open question whether 

 the amino-acids are only indirectly active in this, or whether they form the 

 material from which the sugar is formed. In general we consider the forma- 

 tion of sugar with amino-acids as intermediary bodies as very probable. 



The investigations of WEINLAND 3 tend to prove a sugar formation 

 from protein. He studied the formation of sugar in the chrysalis pulp 

 of the Calliphora and showed that the sugar formed thereby did not orig- 

 inate from the fat, but that the protein was the only material from which 

 the sugar was formed. 



If we assume a formation of sugar from fat, we must differentiate 

 between the two components of neutral fats, that is, between the gly- 

 cerin % and the fatty acids. A formation of sugar from glycerin can 

 be considered as proven by the investigations of CREMER, and espe- 

 cially those of LtiTHjE, 4 and in the following we will discuss only the 

 formation of sugar from the fatty acids. 



1 Baumann, Zeitschr. f. physiol. Chem., 4; Blendermann, ibid., 6; Neuberg and 

 Langstein, Arch. f. (Anat. u.) Physiol., 1903, Suppl.; Mayer, Zeitschr. f. physiol. Chem., 

 42; Lang, Hofmeister's Beitrage, 5.. 



2 Langstein and Neuberg, 1. c.; Cohn, Zeitschr. f. physiol. Chem., 28; F. Kraus, 

 Berl. klin. Wochenschr., 1904; Embden and Salomon, Hofmeister's Beitrage, 5 and 

 6, and with Almagia, ibid., 7; Lusk, Amer. Journ. of Physiol., 22. 



3 Zeitschr. f. Biol., 49 (N. F., 31). 



4 Cremer, Sitzungsber. d. Ges. f. Morph. u. Physiol. Munchen, 1902; Liithje, Deutsch. 

 Arch. f. klin. Med., 80. 



