There has never been a time when, as now, the world has given such careful thought and scientific study to the causes of disease and the most effective measures for its prevention. Within the last decade public health has assumed a new importance. As medical knowledge has become more exact, the needlessness and the costliness of disease have become more evident and the public has joined forces with the advance guard of the medical profession in the development of what is practically a new science—preventive medicine.
In the evolution of this work, certain facts have taken on new relationships and have stood out in greater prominence than ever before. We have come to realize that the social fabric of our modern life is woven together by the forces that make for the physical well-being of the people. We now know that disease is neither an accident nor a mysterious