# Defensive Ferments of the Animal Organism/Preface to the Third Edition

Preface to the Third Edition.
It took less than three months for the Second Edition to be exhausted, a pleasing sign that this new field of research has excited much interest. The number of works which have been completed on the basis of the principles there laid down, and of the methods there disclosed, exceeds one hundred and twenty! Every week brings forth new works. I am not sure whether that ought to give me entirely unbroken satisfaction. The fundamental works, which have arrived at a definite conclusion in regard to the elaboration of the dialysation process and of the optical method, have been produced during the last twelve years or so. The "theoretical" part, which pointed to the possibility of a sero-diagnosis of the functions of organs, was practically established six years ago. Experiments on animals were started on a large scale, so as to allow for all possibilities. Over and over again doubts cropped up which had to be settled. The astonishing result was found that, in disturbances of certain organs, only their albuminous constituents suffer decomposition. These discoveries were not made public, and only those results, which were established in investigations on ​pregnancy, were published. Pregnancy is a condition which allows of no misinterpretation. In almost every case the clinical diagnosis can be compared, with absolute certainty, with the result of the serological diagnosis. The actual diagnosis either corresponds with the former, or it does not. These clear conditions, however, are not presented by the other morbid processes. A certain disease may be accompanied by all kinds of other disturbances of the functions of the organ. Very seldom are we faced with the presence of "pure" disease. Therefore, we are bound to conclude that only the worker in a hospital is in a position to judge, to what extent serological investigations can be applied for testing the functions of an organ. In this case two aims have to be distinguished. The serological diagnosis can, in many cases, widen our understanding of the disturbances occurring in a given disease. We gain an insight into long suspected functional troubles of certain organs, or discover that others, which had never been thought of, regularly produce disturbances in a certain disease. It is an entirely different question to ask whether the serological diagnosis of an organ can be applied to differential diagnosis, i.e., whether we are entitled to accord a preference to this, as against any other, method.
Many years may be required before the question of the practical value of the methods worked out can ​be decided for each separate case. Every research, which has not been carried out with absolutely unobjectionable technique, delays our arrival at a clear appreciation of the suitability of the methods. There are practically no methods which, on first acquaintance, will lead anyone to good results. Often weeks have to be spent in preliminary studies, before facts are acquired which entitle us to apply the required methods to certain questions. No conscientious student would publish these preliminary studies, but would treat them as exercises. Owing to a very extensive experience of my own, I cannot deny that many preliminary studies of this kind have been published. It is only work that is deliberate, and that is based on a complete command of methods, that can lead to satisfactory results. It is, besides, the duty of the clinical worker to thoroughly study each case, and to follow it out to the end.
As yet, it is too early to criticize the works that have appeared, and I have contented myself merely with summarizing such as have come to my notice. Then the results of recent experimental researches have been referred to. The question of the specificity of the substrates is discussed, and, finally, in the description of the technique, some recent experiences have been considered.
Emil Abderhalden.
November, 1913.
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