ORIGIN OF THE LACTIC ACID. 555 



the liver and muscles was always diminished. He also calls attention 

 to the fact that dextrolactic acid may be formed from glycogen, as directly 

 observed by EKUNINA/ and also to the numerous observations on the 

 formation of lactic acid and the consumption of glycogen in muscular 

 activity. Without denying the possibility of a formation of lactic 

 acid from protein, he states that with lack of oxygen we have to deal 

 with an incomplete combustion of the lactic acid derived by a cleavage 

 of the sugar. HOPPE-SEYLER 2 also positively defends the view as to 

 the formation of lactic acid from carbohydrates. He was of the opinion 

 that lactic acid is produced from the carbohydrates by the cleavage of 

 the sugar only with lack of oxygen, while with sufficient oxygen the sugar 

 is burned into carbon dioxide and water. The formation of lactic acid 

 in the absence of free oxygen and in the presence of glycogen or dextrose 

 is, according to HOPPE-SEYLER, very probably a function of all living 

 protoplasm. In the anaerobic metabolism of the animal cells, accord- 

 ing to the recent investigations on alcoholic fermentation in the tissues 

 (see Chapter VIII), carbon dioxide and alcohol are formed from the 

 sugar, with lactic acid as an intermediary step; but even if this view 

 be correct and when the cells, as STOKLASA S and his collaborators have 

 shown, contain a lactic-acid-forming enzyme, it is not known what 

 kind of lactic acid is here produced. MORISHIMA believes that an increase 

 in the lactic acid in the liver occurs after death, probably from the 

 liver glycogen, but this acid is chiefly fermentation lactic acid, and the 

 fact must not be overlooked that INOUYE and KONDO 4 found dextro- 

 rotatory lactic acid on the autolysis of muscles. 



ASHER and JACKSON 5 experimented by transfusing blood (with and 

 without the addition of sugar) through the lower extremities of dogs, 

 and neither in these experiments nor in those where the larger organs 

 (liver and abdominal viscera) were excluded from the circulation could 

 they detect any increase of lactic acid due to the sugar. Although 

 these last-mentioned investigations do not show any formation of lactic 

 acid from carbohydrates, still, on the other hand, we have recent 

 investigations that make such an origin for lactic acid very probable. 

 Thus EMBDEN 6 found, on percolating blood through a surviving liver 

 rich in glycogen, that lactic acid was formed, and also that this acid 

 was produced in abundance when blood rich in sugar was transfused 



1 Journ. f. prakt. Chem. (N. F.), 21. 



2 Virchow's Festschrift, also Ber. d. deutsch. chem. Gesellsch., 25, Referatb., 685. 



3 Simacek, Centralbl. f. Physiol., 17; Stoklasa, Jelinek, and Cerny, ibid., 16. 



4 Morishima, Arch. f. exp. Path. u. Pharm., 43; Inouye and Kondo, Zeitschr. f. 

 Physiol. Chem., 54. 



5 Zeitschr. f. Biologic, 41. 



6 Centralbl. f. Physiol., 18, 832. 



