2?2 ROLLIN T. WOODYATT 



nitrogen in the urine, and in the fasting phlorhizinized dog every gram 

 of nitrogen derived from the body protein and excreted may be accom- 

 panied by 3.65 grams of glucose in the urine. This implies 58 grams 

 of glucose from every 100 grams of protein catabolized. These figures are, 

 of course, not absolute. Unless special precautions are taken, the animal 

 is never strictly free of glycogen. All dogs do not show the same ratio nor 

 any one ratio with perfect constancy. The ratio 2.8: 1 described by 

 Minkowski in pancreas diabetes may also be seen in phlorhizin diabetes. 

 Sansum and Woodyatt(fr), working with completely phlorhizinized dogs 

 that were deglycogenized by epinephrin usually obtained D : N ratios lower 

 than 3.65 : 1. The fat also never disappears entirely from the body al- 

 though it may approach the vanishing point when the experiment is suffi- 

 ciently prolonged and no food is given. Glycerol is capable of quanti- 

 tative conversion into glucose in the body and as long as fat is cataboliz- 

 ing, glycerol presumably must be liberated and be accounted for. In one 

 of our experiments that continued 41/G days (after the ratio had settled), 

 a fasting completely phlorhizinized and deglycogenized dog showed D : N 

 ratios of 3.09, 3.04, 3.24 for 3 successive 6 hour periods on the last day. 

 Ratios of 3.0, 3.04, 3.05 and 2.9 were encountered in the later stages of 

 experiments with other dogs even though earlier these same dogs had 

 for 12 to 24 hours shown ratios between 3.5 and 3.8. This belated falling 

 of the ratio to a lower level suggests, at least, the possible derivation of glu- 

 cose from other sources than protein during the earlier stages. The feeding 

 of fat to phlorhizinized dogs was not observed by Lusk to increase gly- 

 cosuria although glycerol is known to be convertible into its weight of 

 glucose ; but if the body had contained enough fat at the time of the fat 

 feeding, the latter would not necessarily increase the actual catabolism of 

 fat but would act simply as a replacement. Von Norden has pointed out 

 in this connection that the feeding of fat need not of necessity increase 

 the fat catabolism. It is not impossible that when the ratio of D : N is 

 3.65 : 1 other materials catabolizing constantly with the protein may liber- 

 ate a fairly constant small quota of glucose (glycogen, glycerol of fat), 

 which is then credited to the protein. However, the 3.65 ratio is one 

 that is seen not only in phlorhizinized 'dog experiments. Almost the same 

 ratio has been observed in certain cases of human diabetes. (Mosenthal.) 

 It is a ratio better established than any single lower ratio that can be 

 specified and it should be accepted until the claims of another are better 

 substantiated. 



Fat. Fats when catabolized in the body must first be saponified to 

 yield glycerol and higher fatty acids. Ringer reported that propionic 

 acid was convertible into glucose and that certain other lower fatty acids 

 with an odd number of carbon atoms were partly convertible but the 

 ordinary higher fatty acids, all of which have an even number of carbon 

 atoms, have not been found to be capable of forming sugar. Glycerol, as 



