Dr. French begins by saying that doctors' new duty is the prevention of disease, whereas for centuries it had been the cure of disease. With the emergence of serum therapy, physicians have at their disposal the means with which to eradicate certain previously devastating diseases. He then goes on to give examples of how new knowledge of infectious diseases is being put to use in halting a disease's advance in a population by cutting it off at its source. French asserts that isolation hospitals are absolutely necessary in the struggle to stave off and eventually eradicate diseases. He introduces other methods of halting disease spread that are being employed, such as examining public school students in cities and stricter food regulations.
French is optimistic about the future of medicine in the coming century and proud of the major advances made recently. He recognizes that these changes have made doctors preventers rather than healers and that medicine will continue to extend into the realm of disease prevention.