One of the most fascinating tools at the disposal of the molecular biologist is the medical clinic. The responsibilities of those who provide health care do not stop when they give optimal care to the individual patient and train their successors adequately. They also are under the obligation to obtain maximal information from every case they treat in order to reach a better understanding of the underlying illness in order to improve therapeutic results in the next patient. Fundamental research in pathological material is therefore a medical must as well as an opportunity for scientific work. The scientist working in this field can profit from nature's unasked for experiments, which are encountered by his medical colleagues in their clinical material. There are many examples of subjects of study - for instance hemoglobins and immunoglobulins - which started in a medical context and gradually developed into a field of prime interest for the molecular biologist. The study of blood coagulation is one of the younger areas of this kind.

The Boerhaave Courses in Cardiology have been held once or twice a year since 1955. For the greater part they were meant for specialists in Cardiology, Pediatrics, and Internal Medicine, who wished to hear about recent advances in Cardiology and in its anatomical and physical basis. For some time the courses reflected mostly the work in Leiden, especially on congenital heart disease, but soon the highly valuable cooperation of other centres was obtained on subjects in which they had more experience. In later years speakers from abroad were also invited and they con tributed greatly to the wider scope of the courses. It was thus possible to organize detailed discussions on special subjects by panels of experts for an audience of interested clinical specialists. General reviews were also given for widely varying groups including general practioners and health officers. The special courses were usually given in English and were international in character, while the general courses were given in Dutch. This book reports on a course that united both trends. It was held entirely in English mainly because it was combined with a meeting organized by the Dutch Heart Association and because of the support given by the Secretary of Health who opened this meeting personally and by the European branch of the World Health Organization which was represented by Dr. Pisa."

This book comprises the essential records from a Boerhaave course given in June 1971 for specialists in cardiology and other fields of internal medicine interested in the subject of quantitation in cardiology. It is evident that in the wide field of medicine, and particularly in cardiology, there is a growing need for exact and detailed information in conjunction with existing diag nostic methods. This is apparent in the greater precision in anatomical and haemodynamic details required by the thoracic surgeon as the number of available heart operations gradually increases. In retrospect it is hardly surprising that the high initial mortality after the introduction of each operation depended to a large extent upon the degree of accuracy with which the diagnosis was made. Another urgent need for precise and quantitative information became apparent when monitoring of high-risk patients, in order to forestall compli cations and/or death, became routine. The same applies for the diagnostic procedures used to estimate the patient's chances of surviving an operation and/or rehabilitation after a serious incident, such as myocardial infarction. In these fields there is a vast amount of data to be handled and - in modern diagnostic procedures - it must be processed so rapidly that the human mind cannot suffice and computer equipment has becomeindispensable."

Since 1952, postgraduate courses for practising physicians and speci alists have been given by the Medical Faculty of the University of Leiden in the Boerhaave Quarter, in which most of its clinics and laboratories are located. During these years, recent advances in a wide variety of m dical fields and subjects have been discussed by distin guished speakers from many countries. The steadily increasing atten dance has shown that, as could be expected from the rapid progress of modern medicine, there is a widely felt need for this form of postgra duate study. In 1957, therefore, the Leiden Medical Faculty appointed a permanent committee for the organization of postgraduate medical education. Of the courses given since then, certain material proved to have sufficient immediate scientific value to justify publication, and it now gives the Committee great pleasure to announce that in collaboration with the Leiden University Press it will publish the Boerhaave Series for Postgraduate Medical Education. The first volume of this new series is the product of the course on Human Blood Coagulation given in Novem ber 1968. It is our hope that this book will prove valuable not only to those who participated in the course but also to many others working in this and associated fields."

The Boerhaave Courses in Cardiology have been held once or twice a year since 1955. For the greater part they were meant for specialists in Cardiology, Pediatrics, and Internal Medicine, who wished to hear about recent advances in Cardiology and in its anatomical and physical basis. For some time the courses reflected mostly the work in Leiden, especially on congenital heart disease, but soon the highly valuable cooperation of other centres was obtained on subjects in which they had more experience. In later years speakers from abroad were also invited and they con- tributed greatly to the wider scope of the courses. It was thus possible to organize detailed discussions on special subjects by panels of experts for an audience of interested clinical specialists. General reviews were also given for widely varying groups including general practioners and health officers. The special courses were usually given in English and were international in character, while the general courses were given in Dutch. This book reports on a course that united both trends. It was held entirely in English mainly because it was combined with a meeting organized by the Dutch Heart Association and because of the support given by the Secretary of Health who opened this meeting personally and by the European branch of the World Health Organization which was represented by Dr. Pisa.