THE PROTEINS AND THEIR METABOLISM 133 



into glucose in the diabetic animal, the question naturally presented itself, 

 Will these amino acids exert a specific dynamic influence when given to a 

 phlorhizinized diabetic animal? 



In a series of experiments Lusk proved that in spite of the fact that 

 all of glycocoll and alanin are converted into glucose and that none of it 

 is oxidized, it still possesses the power of raising the heat production. The 

 respiratory quotient in all cases remaining at the low diabetic level lends 

 additional confirmation to the belief that none of these amino acids are 

 oxidized in the diabetic animal. 



From all this it becomes evident that the specific dynamic action of 

 protein is a stimulus to metabolism which is given to the body by certain 

 of the amino acids. It is not the result of these substances burning up 

 as a sort of a bonfire, giving rise to free heat. They act as catalytic agents, 

 spurring up the oxidative processes in the cells. The reaction is in reality 

 much more "specific" than Voit and Rubner realized. It seems to reside 

 in certain amino acids and not in others. 



What the significance is of this spurring of metabolism by protein we 

 do not know. All physiologists are agreed that the extra heat is waste- 

 ful and physiologically uneconomical. Advocates of the high protein diet 

 seem to attach a great deal of importance to the sense of well-being a per- 

 son experiences after a meal rich in protein, but whether a psychic state 

 of well-being can be taken into consideration in determining physiological 

 requirements and laws seems highly questionable. The drinking of wine 

 and other alcoholic beverages certainly puts one in a psychic state of 

 well-being, but no one will claim that this is sufficient evidence for its physi- 

 ological requirement. 



