[P]hysician Édouard Séguin believed deeply in the thermometer’s power both as a necrometer and as a general health care tool.

Despite resistance from many of his colleagues in the medical community, he wrote extensively about how mothers and other family members should learn to use thermometers to take and record the temperatures of their loved ones.

To this end, Séguin designed a targeted “mother’s thermometer”. Instead of being labeled according to a Fahrenheit or Celsius scale, it would follow the model of the necrometer, with a simplified “Scale of Vitality”. The scale, which was reproduced in the manual, ran both up and down from 0, which indicated a “standard of health”, to 5, which was labeled “often fatal”.

Via Slate for the full article.