This is commonly known as calcium sulphide. Once an antidote for mercury poisoning, calcium sulphide is now used by Homoeopathic physicians to treat patients with conditions that are infected, often producing pus. These disorders are usually accompanied by mental and physical hypersensitivity and an intolerance of pain and cold.
Sulphur and ground oyster shell and are mixed together and then heated in an airtight container. The resulting powder is dissolved then combined with lactose in a diluting process.