The rapid diagnosis of cholera

A simple method is described for the diagnosis of cholera, literally within seconds, and for the typing of the organism within minutes. Diagnosis is made directly by the microscopical examination of a drop of rice-water stool, using immersion dark-ground illumination, with no adjustment whatever of the lighting, condenser, or objective. It uses the miniature microscope, either in the laboratory, or held in the hand in the absence of a bench, for example at the bedside or in the field. The method depends on the characteristic movement of Vibrio cholerae, on this being instantly visible, under the most difficult conditions if necessary, by the automatic adjustment of the immersion dark ground condenser of the miniature microscope, and on the cessation of the movement of the organism within five minutes of adding a drop of the appropriate antiserum. The method is proving of value in remote areas where cholera is unexpected, where time would be lost in sending a specimen to a properly equipped laboratory, and where isolation of a case may be vital; but it is also claimed to be of value even where cholera is expected and where proper laboratory facilities already exist.