Preface to the English Edition.
It is more than three years since Abderhalden first published his results in regard to the sero-diagnosis of pregnancy. In the course of his general studies on the nature and properties of the ferments in the blood, and on their relations to metabolism, he came across an instance of their specific action, which suggested the possibility of diagnosing the condition of pregnancy by their means. And it was on the basis of the same methods as had been employed years before by himself and his followers in their preliminary theoretical investigations, that he was led to the great discovery of the demonstration of specific ferments in the blood-serum; that is to say, by the use of the optical method and of the dialysation process.
In view of the possibility of the practical application, in medicine, of these new methods of research, for the purpose of making differential diagnoses and of testing the functions of organs in various diseases, they have been taken up by many members of the medical profession. They were first employed by the gynæcologist; but there is now hardly any branch of medicine left in which the application of these new methods has not been attempted, and in the course
