Paracelsus added salt to sulphur and mercury to make three elements of alchemy, creating an elemental trinity. In medicine, Paracelsus believed in the importance of the trinity as sulphur represented a combustible element, mercury represented a fluid, changeable element, and salt represeneted a solid, permanent element. He believed that these three elements accurately represented alchemical medicine. Sulphur represented the soul, salt represented the body, and mercury represented the spirit. Image Source: Public Domain, https://upload.wikimedia.org/wikipedia/commons/f/fd/DeadSeaIsrael5.jpg