N. A. Smorodintsev. Enzymes of the Plant and Animal Kingdoms, Part I (1915) and Part II (1920). Moscow.

Physics at the present time has, perhaps, sometimes had to go against its will and become acquainted with neighboring disciplines in two directions.

On the one hand, the revision of our conceptions of the fundamental concepts—space, time—connected with the principle of relativity, brings physics into contact with philosophy and makes the English term for physics—Natural Philosophy—understandable and closer. On the other hand, the penetration of physicochemical methods into biology and physiology has posed a number of new problems of extraordinary interest for physics itself.

For those engaged in biological physics, Prof. Smorodintsev’s manual on enzymes is exceedingly useful, since it introduces the reader to the circle of such problems as catalysis, fermentation, activation, the action of poisons, anaphylaxis, and so forth. The large amount of literary data gives even the non-specialist reader a broad acquaintance with the subject.

It is very useful for the physicist to become acquainted with the purely chemical interpretation of the question. In the phenomena of living nature, alongside purely physical processes (diffusion, adsorption, coagulation, precipitation, dissolution, etc.), purely chemical reactions are of enormous significance. They are intermingled.

The investigations of V. S. Gulevich and his school make it possible to reveal the significance of such substances as extractives and ferments. Extractives, in view of their

their comparatively small quantity upon isolation may seem not so important for the study of processes in the organism as is actually the case. Their study acquaints us with the products of the breakdown of proteins and other substances in the organism and makes it possible to select, from among possible laboratory combinations of complex chemical products, those that correspond to the living organism. And this is the guiding thread on the path toward one of the remaining tasks of biochemistry—the synthesis of protein molecules.

The insignificant quantities of extract secreted in the organism in no way indicate the unimportance of their role in the organism, but point to the perfection of the organization of those processes, those pathways, which rapidly remove from a given organ the products of metabolism that are formed.

As for enzymology, it requires no such preliminary remarks. Vital processes are accelerated by enzymes. The force of action of biological reagents is enormous. Lactase hydrolyzes a 5% solution of milk sugar by \(1/4\) within an hour; for the same effect, twice-normal hydrochloric acid requires 5 weeks.

Smorodintsev dwells on the theories of enzymatic action and sets forth the results of Sakharov’s work, which reduces the action of enzymes to processes of reduction and oxidation. It is interesting to note that the role of iron in enzymatic processes finds an analogy in photochemical processes with chlorophyll according to new English works. In conclusion one should mention the chapter “Chemical Dynamics of Enzymatic Reactions,” in which paths are indicated toward the mathematical treatment of the experimental results obtained. This method of treatment, one must think, will soon become firmly established, since it alone makes it possible to carry out exact quantitative accounting.

B. Ilyin.