Infection and Resistance [antikvár]

PREFACE TO THE THIRD EBXTIÖtf The subject of iromimity shares with other branches of biology the difficulties, as well as the attractiveness, of being constantly subject to alteration of point of view and conception. The fact that it deals with problems closely related to medicine, while at the same time its observed phenomena represent, in many cases, fundamental biological laws, attracts workers of many varieties of training, and the evidence by which it grows, emanates from many different sources. The clinician, the statistician, the epidemiological field worker contribute equally with the laboratory investigator, and the development of the past decade has been particularly characterized by the increasing application of the methods of chemistry and physics to its problems. While our subject is, as yet, far from what we may speak of as an exact science, it has already made considerable headway toward this possible goal by enlisting the interest of biologists, chemists and physicists; and no one who is following the subject can fail to appreciate the far-reaching effects upon it that may be looked for from work like that of Landsteiner on the chemical alteration of antigens, and of Loeb's important studies on proteins and colloidal behavior. The worker in immunity who would seek for new methods of approach cannot afford any longer to neglect the guidance of the fundamental sciences. At no time have the experimentál possibilities of this subject been greater or more attractive, but at no time, alsó, has there been such a rapid readjustment of point of view in many of its phases. Failure to appreciate this would make a treatise like this book thoroughly antiquated and worthless in a few years. In rewriting the book we have considerably altered the arrangement of material into what appears to us a more logical sequence. We have omitted the final chapter on colloids by Prof. Young, included in former editions, largely because excellent books on colloidal chemistry, such as those of Williams and of Bancroft, are now available, and because the principles of this subject are, at the present time, more generally familiar to students of infectious disease than they were formerly. A considerable part of the material bearing on this subject has been incorporated in the text wherever applicable. All new material accessible to us which we have considered well founded on experiment and observation has been included, and new opinions and observations, though often still in the balance, have vii