SCOURGES OF MODERN WARFARE
Of the diseases which assail an army in the field, a few stand out so prominently that all others may practically be neglected. These are cholera, typhus, typhoid fever, dysentery, and pneumonia; and they have this in common, that they are all caused by specific bacilli. Thus cholera is the child, so to speak, of the dreaded vibrio, and pneumonia that of the pneumococcus; while typhus, typhoid and dysentery have each their own special microbe. The modes of attack are, however, different, for the pneumococcus can enter the organism by the nose and mouth only; typhoid and dysentery through the alimentary canal; while the way in which cholera is propagated is at present unknown. All have this in common, that while the microbes causing them are probably always present—that of cholera being a doubtful exception—they seem only to assault a subject previously weakened by exposure, bad food, or intemperance.