B. Structure and Physico-Chemical Composition of Bacteria....... .14 C. Qualitative Behavior of Simple Synthetic Systems and the Types of Mutual Combination... I. Qualitative Work on Simple Systems. II. Nature of Mutual Combination of Cell Constituents. An Experimental Isoelectric Point for a Simple System of Two I. Concept of a Conjugate Protein. 18 18 19 20 -20 II. Apparent Isoelectric Behavior........ _20 III. Electrophoretic Behavior.. 21 IV. The Hydrogen Ion Concentration of a Mixture of Two 22 V. Quantitative Experimental Work on Simple Systems__-_-_22 E. Formulation of Equilibria Governing the Amphoteric Behavior of Complex Systems.. __25 Chapter III-WORK ON DEAD ORGANISMS. 29 A. The Isoelectric Range and the Isoelectric Point of the Organism as an _29 B. Speed of Attaining Equilibrium.. The arrangement of material in the following study may seem a bit peculiar. The description of the experimental work is deferred until after a general discussion of the problem is presented, and a general theory of the physico-chemical structure of bacteria given. Although such an arrangement does not parallel the order of development of the work, it is made for two reasons. In the first place, these theoretical considerations, while in complete accord with the experimental data given later, are not merely ad hoc attempts to force coherence into these data. The considerations are much more general, and bacteria are merely particular systems whose behavior is in accord with predictionis based on the picture. In this respect the authors have been interested in, and somewhat influenced. by, the recent development of the theory of atomic structure. In this country a rather suggestive theory was outlined not many years ago to explain mainly certain chemical properties of the atom. These properties it certainly did explain, and explain well, but such was its specific function, and its limitations were marked from the first.67 In 1913 Bohr12 investigated the results of applying certain fundamental laws, which had been formulated in entirely different connections, to the problem of atomic structure. The theory he put forward was not especially designed to explain any particular set of phenomena, though a general interest was at once aroused, since it did seem to account well for certain spectroscopic data. For a time the one was often referred to as the chemists' theory of the atom and the other as the physicists' theory. But it is interesting to note that at the present time even chemists are turning their attention more and more to that theory which attempted no particularate explanations but which was based on general fundamental principles, and are beginning to investigate molecular structure and chemical bonds from its point of view.90 104 In the second place, the authors have found the point of view which is here developed of great assistance in a critical reading of the literature on bacterial behavior, and feel that it is a contribution of just as much, if not of more, importance than the experimental data presented, and should not be treated merely as discussion of these data. Supplementary discussions of particular points have been inserted, where it was deemed advisable, and these partake more of the ordinary discussion of particular data. The authors are, in fact, in complete accord with the attitude of Professor Noyes, who, in speaking of the philosophy of science, says: "Some have gone so far as to claim that speculations and hypotheses form no part of genuine science, ... that the discovery of new facts is of supreme value in science, and that one is doing good scientific work when he adds a few facts to our already unwieldy accumulation of knowledge whether the facts discovered have any valuable relation to fundamental principles or not. ... A more true philosophy of science as it seems to me recognizes the intimate connection between speculation, hypothesis and theory on the one hand, and the accurate study of phenomena on the other. Neither is complete and sufficient alone. ... Speculation alone led to the useless dialectics of the school-men. A study of phenomena alone leads to an almost equally barren accumulation of facts for which we have no earthly use." The "discussions" which many whom Noyes might call "factual scientists" permit themselves to indulge in are, it seems to the present authors, in many cases no discussions at all, but are largely confined to a pointing out of the obvious, and while important as a type of summary, good for reference as to scope and findings, do not permit the reader to get the meaning which the results have for those who obtained them. For those who are interested primarily in the experimental work on bacteria, Chapters I and II may seem to form a disproportionate part of the study. If such be the case they may turn at once to Chapter III; but it is hoped that the last two chapters may possess much more significance in the light of the matter given especially in Chapter II than taken alone. The authors wish also to take this opportunity of gratefully acknowledging the continued encouragement they have received through the active interest of Dr. M. P. Ravenel throughout the development of their problems. Their thanks are also tendered for his careful reading of the manuscript of the present study and his suggestions for its improvement. |