There was another leading idea of Calmette's which we have followed first in relation to tuberculosis, later in dealing with other diseases. Like Calmette we have stopped wholesale drugging, and put our trust in those scientific hygienic procedures which carry out our knowledge of the nature of the disease which we are combating. Calmette's measures have the tone and the point of view of preventive medicine, and of that sound science which we have learned to associate with the Pasteur Institute and all that development of medicine which took its rise from Pasteur. The focussing of interest upon a single disease which began, so far as I know, with Calmette's anti-tuberculosis dispensaries, has been fruitful in many ways. In the first place, it has enabled science once more to _conquer by dividing the field_, to help humanity by devoting itself to a single manageable task. Like others of Calmette's ideas, this isolation of a single disease for group treatment in dispensaries has been followed in fields with which he never concerned himself. Thus we have had special classes for cases of heart disease, for diabetes, for syphilis, for the digestive disturbances of infancy, and for poliomyelitis. A valuable measure of success has come in each of these diseases through the concentration of attention, at a special day and special hour by a special group of physicians and assistants, upon one disease at a time. We have even used class methods and taught the patients in groups as scholars are grouped and taught at school.