108 



A. I. RINGER 



Lactic acid 



COOH 



Alanin 



Pvmvie acid 



COOH 



Of the two substances lactic acid is always and completely converted into 

 glucose (Mandel and Lusk, 1906). Pyruvic acid, however, while it also 

 goes over into glucose, does not do it in a quantitative way (Ringer, 1913 

 (&)). Dakin and Dudley assumed the transformation of lactic acid into 

 glucose in the following way : 



CH 3 

 HOCK 

 COOH 



CH 3 



I 

 HCOH 



CIL 

 CO 



COH 



CH 3 



CO 



CH.OH 



HCOH 



COH 



CH 2 OH 



HCOH 



CILOH 



I 

 HCOH 



I 

 HCOH 



HOCH 

 HCOH 



COOH COH COH COH 



2 Lac'tic acid Pyruvic 2 Glyceric Glucose 



Aldehyd aldehyd 



a-Amino butyric acid.has not been investigated properly. In one single 

 and uncorroborated experiment the giving of 10.3 grams of the substance 

 to a phlorhizinized animal was followed by the excretion of 3.0 grams of 

 extra glucose (Ringer, unpublished). On theoretical grounds this sub- 

 stance may be assumed to give rise to propionic acid, which was shown 

 to be converted into glucose. 



CH. 



CH. 



COOH 



CO, 



Glucose 



