314 Biological Chemistry. 



relationships between carbohydrates on the one hand and 

 fats and proteins on the other. Animals which have been 

 completely deprived of their pancreas lose their capacity 

 for utilizing carbohydrates, and continuously excrete 

 dextrose in the urine. This excretion continues even 

 when the animal has been deprived of food. It seerns 

 unlikely that the dextrose continuously excreted after the 

 deprivation of food can be derived entirely from the carbo- 

 hydrate store in the organism. If this is not the case, it 

 must be formed either from the protein or the fat store of 

 the body. It has been shown by Liithje that the adminis- 

 tration of proteins to the starving diabetic animal is 

 immediately followed by a largely increased output of 

 dextrose in the urine. Ammo-acids can also produce a 

 similar effect. Experiments of this character appear to 

 indicate the possibility of the formation in the body of 

 carbohydrates from proteins and their degradation products. 

 Probably the first action is that of deaminization ; alanine, 

 for example, would give rise to CH 3 -CH(OH)-COOH, 

 lactic acid. It is possible to conceive the formation of 

 dextrose from such a substance by a series of reactions, 

 but many of the stages in the change are at the present 

 moment so problematical that a further discussion of the 

 possible reactions would be unprofitable. The results are 

 quoted in this place chiefly as an example of a method for 

 the investigation of the intermediary metabolic changes. 



(E) METHOD BY CHEMICAL EXAMINATION OF THE BODY, OR 

 ORGANS OF THE BODY, OF AN ANIMAL AFTER ADMINI- 

 STRATION OF CERTAIN FOODS. 



A classical example of this method is afforded by the 

 experiments of Gilbert and Lawes on the formation of fats 

 from carbohydrates. Two young pigs, ten weeks old, from 

 the same litter, and of approximately equal weight, were 



