4Q2 POPULAR SCIENCE MONTHLY 



point of view, viz., that the processes of animal metabolism are peculiar 

 and are by no means always concomitant with ordinary oxidation. 

 Outside the animal body, the customary components of our daily food, 

 the proteins, fats and carbohydrates, are not affected by oxygen even at 

 the body temperature or by long exposure to the gas. Catalytic action 

 is a necessary prelude to their oxidation, and it is the smaller molecules 

 resulting from the action of enzymes working through catalysis that 

 are mainly burned up or broken down with liberation of their contained 

 energy. 



The processes of nutrition are truly complicated, and we can readily 

 conjecture that their harmonious working is dependent in large measure 

 upon the integrity of many closely related operations. Enzymes must 

 be elaborated in due proportions, both in digestive secretions and in 

 tissue cells; proper conditions for enzymolysis must prevail at the 

 places where the reactions take place, since enzymes are extremely 

 sensitive to their environment and fail to work unless all the require- 

 ments are fully met; proper conditions of circulation of blood and 

 lymph must be maintained, in order to supply fresh pabulum and to 

 prevent undue accumulation of the products of enzymolysis. In short, 

 there are a multitude of accessory reactions to be preserved in their 

 proper sequence and normal rhythm if perversions of nutrition are to 

 be avoided. Many a substance known to have a deleterious effect upon 

 nutrition does so in virtue of its action upon some one or more enzymes 

 with which it may be brought in contact in the body. Take, for 

 example, the well-known influence of alcohol as a factor in the causa- 

 tion of gout. In this disease, there is an increased amount of uric 

 acid in the system, due in part to an inhibition of its oxidation and 

 consequent destruction. When alcoholic fluids are taken, together with 

 an excess of meat or kindred animal foods, the kidneys at once excrete 

 increased amounts of uric acid, in harmony with the increased content 

 in the blood. It is a well-known fact that alcohol interferes with the 

 oxidative processes in the liver. It is equally well known to-day that 

 the liver and other organs contain an enzyme, or more specifically an 

 oxidase, which has the power of oxidizing uric acid to urea and other 

 products. After the ingestion of alcohol and animal foods rich in 

 uric acid precursors, the notable increase of uric acid in the blood and 

 urine is considered as due to the inhibitory action of alcohol on this 

 oxidase, which under normal conditions causes more or less destruc- 

 tion of uric acid. The failure of the enzyme to accomplish its ordinary 

 duty naturally results in an accumulation of uric acid in the system, 

 although the kidneys plainly endeavor to meet the new conditions by 

 increased elimination. Hence, we see that the predisposition to the 

 development of gout caused by the ingestion of a high protein diet 

 reinforced by alcohol is to be explained in part at least by the direct 



