Svante Arrhenius. Quantitative Laws in Biological Chemistry. London, 1915. (164 pp.).

The development of biological chemistry has proceeded in several different directions.

At first, the most natural thing was to turn directly to the object under study, to the living organism, and to apply to it the method of chemical analysis, seeking to isolate, in a chemically individual state, those substances, mineral and organic, which enter into the composition of plants and animals, and then to clarify for oneself the role of these substances in vital chemical processes, their significance for the phenomena of life in general.

This direction arose during the first half of the 19th century. Its most brilliant representative and one of its founders was Justus Liebig, although it had been indicated considerably earlier by the works of Lavoisier.

When analytical investigations had cleared and prepared the ground, another direction soon began to develop rapidly. The complex organic compounds that play such an important role in the phenomena of life began to be studied not only in greater detail from the point of view of their chemical structure, but efforts were also made to obtain these compounds artificially, starting from simpler components and imitating the processes occurring in the organism of plants and animals. This is the direction of modern synthetic chemistry, opened by the brilliant works of M. Berthelot and completed by Ad. Baeyer, E. Fischer, and a number of other outstanding chemists of our time.

Alongside substances that are fully definite and readily lend themselves to isolation from mixtures in a pure state, alongside substances whose composition, structure, conditions of formation, and transformations can be established—in living organisms there also act such agents which, because of their extraordinary complexity, low stability, and perhaps for other reasons as well, do not yield to study in the above-mentioned respects. Such are enzymes, which act as catalysts, accelerators, and stimulators of chemical reactions and play an exceptionally important role in biochemical processes; such are toxins, special and for the most part extremely powerful poisons produced by certain bacteria (the toxins of diphtheria, tetanus, etc.), by plants (ricin, abrin), and by animals (snake venoms); such are antitoxins, specific antidotes against strictly definite toxins, produced by animal organisms in response to the introduction of increasing doses of the corresponding poison. All these substances have not yet been isolated in pure form; we know almost nothing about their chemical composition. Concerning enzymes we at least know what kinds of reactions they excite, but concerning toxins and antitoxins and a number of oth-

of such analogous bodies we do not know even this. If we were to begin applying to their study the classical methods of biological and organic chemistry, successfully tested in a number of cases, we would suffer a complete fiasco, and we would have to abandon research in this direction altogether.

Fortunately, a certain way out is provided by the application to this peculiar field of methods of investigation, theoretical devices developed by physical chemistry.

Physical chemistry makes it possible to treat chemical processes, to investigate the laws to which they are subject, to establish the mutual connection between them, without concern, or with little concern, for which particular substances enter into interaction, and to what transformations they are subjected. It is possible to determine the character (for example, reversibility or irreversibility, “order”) of a reaction proceeding between unknown bodies, to establish the influence upon it of physical and chemical factors (for example, the influence of temperature on equilibrium), etc. The results obtained, despite their somewhat abstract character, have great scientific value and contribute much to the understanding of the phenomena taking place in the organism.

Among the investigators who have entered upon this path of treating biochemical problems, one of the first places must be assigned to Prof. Svante Arrhenius, one of the creators of modern physical chemistry, now holding the post of director of the Nobel Institute in Stockholm.

In the book whose title is given above, representing a collection of lectures delivered by Prof. Arrhenius in America, there is a summary of certain results obtained both by the author himself and by other scientists in the study of a number of biochemical phenomena from the just-indicated physico-chemical point of view. For a number of “obvious,” so to speak, biochemical processes, he analyzes the applicability of the fundamental laws of chemical dynamics, such as: the law of mass action, the influence of temperature on the rate of reaction and on the displacement of equilibrium in reversible processes, etc. In more detail the author dwells on those subjects with which his own investigations in this field were connected. These include the question mentioned above of toxins and antitoxins and the closely related question of hemolysis, then the study of enzymatic reactions, with special attention being given to the digestive process, etc. (These investigations of Svante Arrhenius, in part, had earlier been set forth in extenso and collected in the book Svante Arrhenius, Immunochemie, Leipzig, 1907).

Without dwelling here on a number of other most interesting questions touched upon in Arrhenius’s book, let us note in conclusion that, with originality and freshness of thought, it combines simplicity and accessibility of exposition. We warmly recommend it to the attention of chemists and naturalists,

those interested in what is being done in a field of knowledge only recently born, lying on the boundary between chemistry and biology, and promising still to yield many valuable results of the first scientific importance.

L. Chugaev.