SOME NEW VIEW POINTS IN NUTRITION 399 



When Buchner a few years ago, by simple pressure, forced from 

 the yeast cell a little limpid fluid and with this was able to induce the 

 same chemical reactions that the living yeast plant produces when 

 brought in contact with a sugar solution, it became clear that the typical 

 formation of alcohol and carbon dioxide is not the result of the life of 

 the yeast plant as formerly supposed, but is instead to be attributed to 

 something — a chemical substance — easily separable from the yeast 

 cell, and quite capable of causing the fermentation of sugar. This 

 reaction, which had for so long been looked upon as a typical illustration 

 of the power of life in inducing chemical change, is merely a simple 

 process of enzymolysis. The yeast plant, it is true, produces the en- 

 zyme; but the isolated ferment, once formed, is just as capable of 

 decomposing the sugar as the yeast plant itself. Indeed, the latter is 

 able to accomplish this chemical reaction, solely because of the pres- 

 ence of the enzyme or ferment, now called zymase. In all forms of 

 animal and vegetable tissue, intra- and extra-cellular enzymes abound; 

 enzymes of varied nature, endowed with the power of inducing chem- 

 ical reactions of diversified character. Those previously referred to 

 in the breaking down of protein material, both in digestion and in 

 autolysis, are typical of what may be found in many of the fluids and 

 in most of the tissues of living organisms. Enzymes which induce 

 hydrolytic cleavage are especially abundant; sugars, proteins and fats 

 all falling as prey to their power of breaking down the respective 

 molecules into smaller and simpler ones better fitted for distribution 

 or utilization. Further, enzymes of the amidase type, which have the 

 power of removing nitrogen from nitrogenous compounds, are equally 

 conspicuous in many phases of intermediary metabolism, especially 

 where changes of nuclein material are involved. In this reaction the 

 elements of water are apparently alone involved, but in some mysterious 

 fashion the enzyme causes a retention of oxygen while the hydrogen 

 passes off with one atom of nitrogen in the form of ammonia, thus 

 leading to the formation of a new substance with one more atom of 

 oxygen than the body from which it was formed and with one less atom 

 of nitrogen and of hydrogen. In this way, gradual oxidation results 

 without free oxygen being involved, while at the same time the content 

 of nitrogen is reduced. Again, there are enzymes separable from the 

 tissues of the body which bring about the destruction of uric acid, not, 

 however, by a process of annihilation, as might be implied by the above 

 statement, but by a method of cleavage in which new bodies less com- 

 plex are formed. Equally manifest is the action of enzymes which 

 bring about glycolysis, i. e., the destruction of sugar as in the blood; 

 while the separation of the amido group from amino-acids, the oxida- 

 tion of aromatic aldehydes, the splitting apart of a substance like 

 arginine into urea and ornithine, and a host of kindred reactions, all 



