being manufactured it was done through sublimation. Calomel made through sublimation tends to be a very fine white powder. There was some controversy over the sublimation of calomel. Many argued that the more times calomel was sublimed, the purer it got. Opponents believed that the repeated sublimation made calomel lose some of its therapeutic ability. In 1788 chemist Carl Wilhelm Scheele came up with the mechanism to make precipitated calomel. This became rapidly popular in the pharmaceutical industry because it was both a cheaper and safer form of production. Precipitation also tended to form very pure calomel salts. Medicine Calomel was a popular medicine used during the Victorian period and was widely used as a treatment for a variety of ailments during the American Civil War. The medication was available in two forms, blue pills and blue masses. The blue pill was an oral form of calomel containing mercury that was often mixed with a sweet substance, like licorice or sugar in order to be taken by mouth. The blue mass was a solid form of calomel in which a piece could be pinched off and administered by a physician or other medical provider. Neither form of the medication came with a standardization of dosing. There was no way of knowing how much mercurous chloride each dose contained. Uses Calomel was marketed as a purgative agent to relieve congestion and constipation; however, physicians at the time had no idea what the medication’s mechanism of action was. They learned how calomel worked through trial and error. It was observed that small doses of calomel acted as a stimulant, often leading to bowel movements, while larger doses caused sedation. During the 19th century, calomel was used to treat numerous illnesses and diseases like mumps, typhoid fever, and others—especially those that impact the gastrointestinal tract, such as constipation, dysentery, and vomiting. As mercury softened the gums, calomel was the principal constituent of teething powders until the mid-twentieth century. Babies given calomel for teething often suffered from acrodynia. Side effects It became popular in the late 18th century to give calomel in extremely high doses, as Benjamin Rush normalized the heroic dose. This caused many patients to experience many painful and sometimes life-threatening side effects. Calomel, in high doses, led to mercury poisoning, which had the potential to cause permanent deformities and even death. Some patients experienced gangrene of the mouth generated by the