JACQUES LOEB

P. P. Lazarev.

On February 11, 1924, one of the most interesting and profound thinker-physiologists, and one of the finest men—the American biologist Jacques Loeb—went to his grave. Nothing foretold his rapid end, and his death, which overtook him in the midst of his work, in the prime of his intellectual powers, came as a complete surprise to everyone.

A convinced mechanist in the sense of Descartes, Loeb carried these views through all his work, and his investigations constitute an entire epoch in biology.

Here, first of all, one must point to his works in the field of artificial parthenogenesis (artificial fertilization), which are exceptional in importance and in their consequences. In his works in this field Loeb proceeded from the idea that the transition of the egg from a state of rest to a state of activity must depend on chemical processes caused by the fertilizing element. In a number of lower animals Loeb experimentally proved that, by acting on the egg with salts, one can make it begin to divide and form an embryo, which, however, could not reach the state of an adult organism, since it was very difficult to find suitable conditions for the nutrition of the embryo.

In these investigations, about which Loeb wrote two books, he discovered a remarkable law of growth, representing complete identity with the law of an autocatalytic chemical reaction, i.e., a reaction that accelerates itself; after his investigations it must be considered that in the process of artificial (and therefore, very probably, also natural) fertilization we are dealing with a reaction caused by the presence of ions and accelerating itself, this acceleration of the reaction creating the increase of substance that constitutes the increase in weight of the growing organism. This idea of the simple chemical foundations of growth found brilliant confirmation in a series of subsequent works by Loeb and his pupils, and he found the manifestation of the fundamental law of chemistry—the law of mass action—in the phenomena

regeneration of plant and animal tissues, in the laws of stem growth, etc. These phenomena occupied Loeb in recent years, and during my stay in America in the winter of 1923 I saw these latest remarkable investigations of his. The basic idea—that the processes of growth and regeneration of tissues are the results of the fundamental laws of chemistry—already now appears quite clear.

Loeb’s works on parthenogenesis did not immediately find recognition. Many biologists, not understanding the physico-chemical method of approach to the solution of biological problems, raised a mass of petty objections, entirely beside the point, and only hindered the understanding of the basic fact. At the root of all the objections lay, in a concealed or semi-concealed form, the vitalistic notion that in the process of fertilization the presence of living substance is necessary, and not salts. And when Loeb could not bring the development of embryos to completion, his opponents pointed out that between artificial and natural fertilization there is no complete analogy, that in one case we have only an impulse to development and that in the other, on the contrary, there is full harmonious development. Loeb gradually tried to remove all factual objections, and the crown of his work in this respect is the higher organisms that developed parthenogenetically, about which he wrote only very recently, and preparations of which I was able to see in his laboratory.

The struggle waged by Loeb to secure the results he had obtained is unusually clearly characterized by his “fighting nature” — in the splendid obituary by Prof. Storm von Leeuwen (Storm von Leeuwen).

The physico-chemical direction of Loeb’s work, insufficiently appreciated by biologists, found ardent adherents among physical chemists, and Loeb had long been a close friend of Arrhenius, who dedicated to Loeb his book on the foundations of biochemistry.

From what has been said it is clear that in questions of life Loeb was a consistent mechanist. This fundamental idea of mechanism permeates Loeb’s last published work on the organism as a whole, where Loeb consistently develops the idea of the organism as a complex physico-chemical mechanism.

Naturally, Loeb’s idea, carried in a straight line and consistently through the whole work, could not please the vitalists, and Loeb said that many of his acquaintances among the vitalists reacted to his book with disapproval1.

The second large group of Loeb’s works consists of his investigations on colloids. Understanding that knowledge and a clear conception—

knowledge of processes in the living organism can be obtained only by studying the fundamental properties of proteins. Loeb attached enormous importance to the physico-chemical approach to this question, and his wartime works embrace a large number of brilliant investigations in the field of colloid chemistry. Here Loeb succeeded in showing that the scattered regularities observed by other investigators, often contradicting one another, can receive a complete explanation if we take into account that colloidal processes can be compared only under identical conditions, when the concentration of hydrogen ions, which strongly affect the properties of the colloidal substance, is one and the same. By preparing such solutions with the same content of hydrogen ions, Loeb was able to show that under these conditions colloids obey the ordinary laws of chemistry, and that there is no basis for singling out this branch of chemistry as a separate discipline.

These works were collected by Loeb and printed in the form of a monograph (Proteins and the Theory of Colloidal Behavior). His large article on the same subject, published in Nature and Naturwissenschaften, was, with Loeb’s kind permission, translated and printed in the preceding issue of our journal.

My correspondence with Loeb began as early as 1910, when I, for the first time, relying on the facts established by him, gave an expression for the general law of excitation and applied it to the case of electrical irritation of nerves and muscles. This work elicited Loeb’s ardent support, and the appearance of the works that followed was each time met by him with great sympathy. During the war my correspondence with Loeb was interrupted, and my attempts to send him letters and works were unsuccessful. The letters and works did not reach him. Finally, in 1920, when communication with abroad had already begun, I succeeded, through one of the scholars sent abroad, in forwarding to him all our works, and in reply to this Loeb immediately wrote a letter in which, with the ardor characteristic of him, he offered every kind of support for the work; and when I informed him that I did not have American journals, I at once received not only the Journal of General Physiology, which he edited, but also a mass of works carried out in America, and in almost every subsequent letter Loeb unceasingly repeated that I should write to him about all difficulties in the work of Russian scholars.

Until 1923 I had had no occasion to meet Loeb personally. In 1923 I was invited by the Amerikan Association to deliver a report at the association’s annual jubilee (75-year) meeting in Cincinnati, and in New York I was able to become personally acquainted with Loeb. For the first time I was able to see the man whom I knew closely from letters and whose work I highly valued. During my stay in New York I saw Loeb daily, and sometimes even three times a day. And from the very first day I felt that before me stood not only a great scientist, but

and a great man in the best sense of the word, one who warmly sympathized with everything good, an ardent supporter of new currents in natural science, who loved science and those who work in it to the point of self-forgetfulness. Especially touching was Loeb’s concern for young scientists. I had occasion to see how keenly Loeb was interested in the fate of one beginning chemist, and how much he tried to do for him, using every possible means to give him the opportunity to carry on scientific work.

As in his writings, so also in personal relations, Loeb was a sincere and truthful man to the end. He admitted his mistakes, if he had any, and warmly supported every initiative of a scientific and social character. Gentle and kind, Loeb could not endure lies; this won him ardent admirers, and it also made him enemies.

Loeb’s death is a severe blow to science, an irreparable loss for the Rockefeller Institute, to which he gave almost half of his life, and his death is a great loss for Russian scientists.

1. This book, as well as the book on tropisms, will shortly appear in Russian. ↩