332 THE METABOLISM OF THE CARBOHYDRATES 



of the glycogen. In others, egg-white was used, but, as we have 

 seen, there is a considerable amount of carbohydrate in this form 

 of proteid. 



By far the most exhaustive researches on the derivation of glycogen 

 from proteid, as tested by the direct method, are those recorded by 

 E. Kiilz ( 6 ). This worker experimented on pigeons and hens. In 

 pigeons he found that after two to four days' starvation the average 

 amount of glycogen in the liver and muscles was 0*946 grm. per kilo 

 body weight, the maximal amount being 1/259 grm., and that after 48 

 days' starvation the liver was glycogen-free (Briicke -Kiilz method) ; 

 but that the muscles still contained glycogen to the extent of 0*716 

 per kilo body weight, the maximal amount being 1414 grm. These 

 averages were obtained by observations on thirty-three birds. In two 

 cases proteid in the form of flesh powder which had been extracted 

 till no glycogen could be detected in it was fed to pigeons which had 

 been starved for three and seven days respectively. An average of 

 2 - 03 grm. glycogen per kilo body weight was found after the pigeons 

 had been fed for fifteen and twenty-five days on the proteid. We 

 have seen, however, that after from four to eight days' starvation there 

 may still be 1-414 grm. glycogen per kilo body weight, so that the 

 positive increase of glycogen in the above experiments would only 

 amount to 0-616 grm. (2-03-1-414), which amount might well be ac- 

 counted for by traces of glycogen in the flesh powder, too small 

 indeed to give any chemical reaction, yet sufficient in toto to yield 

 a considerable amount of glycogen seeing that during the experi- 

 ment 1058 grm. water- and ash-free flesh powder, representing about 

 5 kg. fresh flesh, were administered. Much of the flesh used, too, 

 undoubtedly underwent slight putrefaction before all the glycogen 

 had been extracted, and by this process much of the glycogen had 

 doubtless become converted into dextrin, which would not be detected 

 by the Briicke-Kiilz method. 



The experiments on hens were conducted on the same plan. 

 After from six to seven days' starvation the average amount of glycogen 

 in the liver and muscles per kilo body weight was found to be 0*656 

 grm., the maximal amount being T605 grm. After feeding hens pre- 

 viously starved for three days with flesh powder for periods varying 

 from eight to forty-three days, it was found that on an average 1-634 

 grm. glycogen per kilo body weight had been deposited in the liver 

 and muscles. This is almost the same as the maximal amount found 

 for starving hens, viz. 1*605. 



From such results as these Pfliiger remarks that we can only 

 conclude that " notwithstanding excessive flesh feeding, no deposition 

 of glycogen had occurred." 



With fibrin, serum, and egg albumin and casein similar results 



