i LACTIC ACID FORMATION FROM SUGAR. 333 



speak positively for the statement that in glycolysis a formation of lactic 

 acid from the sugar occurs. 



That a formation of lactic acid from glucose, and indeed by means of 

 the leucocytes, takes place in glycolysis was shown by LEVENE and MEYER 

 before EMBDEN and collaborators. On continuing these investigations 

 LEVENE and MEYER found that fructose as well as mannose and galactose 

 under the same conditions with leucocytes, yield d-lactic acid while with 

 the investigated pentoses, arabinose and xylose, this is not the case. Accord- 

 ing to EMBDEN and co-workers, this formation of lactic acid takes place 

 probably with glyceric aldehyde, and perhaps also with small amounts 

 of dioxyacetone, as intermediary steps, and a formation of lactic acid from 

 glyceric aldehyde (and dioxyacetone) can in fact, as A. LOEB and GRIES- 

 BACH l have shown, be brought about by enzymotic means by the form- 

 elements of the blood. It seems as if several enzymes were active in the 

 formation of lactic acid from glucose. According to LOEB those varieties 

 of blood which show no glycolysis with the formation of lactic acid, or 

 none worth mentioning, can form lactic acid from glyceric aldehyde 

 and according to GRIESBACH in this last -mentioned process an enzyme 

 is active which is soluble in water and resistant toward the haemolysis 

 of the blood with water, while the action of the blood upon glucose is 

 destroyed in the destruction of the form-elements by haemolysis. In 

 regard to the formation of lactic acid from methyl glyoxal see page 584. 

 According to LEPINE and BOULUD a double process takes place in the 

 glycolysis. On one side the sugar is destroyed and on the other side 

 a re-formation of sugar from the "sucre virtuel" takes place. Hereby the 

 actual glycolysis may be greater than the visible, and the mentioned 

 investigators have therefore suggested a method for determining the 

 extent of the actual glycolysis. 2 



The quantity of urea, which, according to SCHONDORFF, is equally 

 divided between the blood-corpuscles and the plasma, is greater on tak- 

 ing food than in starvation (GREHANT and QUINQUAUD, SCHONDORFF) 

 and varies between 0.2 and 1.5 p. m. In dogs SCHONDORFF found in 

 starvation a minimum of 0.348 p. m. and a maximum of 1.529 p. m. at 

 the point of highest urea formation. GOTTLIEB obtained much lower 

 results by another direct method, namely, in starvation 0.1-0.2, and 

 after meat feeding 0.28-0.56 p. m., FOLIN and DENIS found 0.3-0.77 

 p. m. in the blood of the cat. In man v. JAKSCH S found 0.5-0.6 p. m. 



1 Levene and Meyer, Journ. of biol. Chem., 11 and 14; A. Loeb, Bioch. Zeitschr. 

 49 and 50; Griesbach, ibid., 50. 



2 Lepine and Boulud, Journ. de Physiol., et de Path, generate, 13. 



3 Grehant et Quinquaud, Journ.de 1'anatomie et de la physiol., 20, and Compt. 

 Rend., 98; Schondorff, Pfliiger's Arch., 54 and 63; Gottlieb, Arch. f. exp. Path. u. 

 Pharm., 42; Fob'n and Denis, Journ. of biol. Chem., 11 and 12; v. Jaksch, Leyden- 

 Fetschr., I, 1901. 



