Arsênio e mercúrio em Steiner (2007)

Those that are commonly called the stimulant effects are indeed the most important of all. Precisely the substances people think inessential are present all around the Earth — actively working, though in the finest and most tenuous dilution. Moreover, the plants need them just as much as they need what comes to them from the Earth. They draw them in from the world-circumference — from the cosmic circle. Mercury, arsenic, silicic acid — these substances the plants suck upward from the soil of the Earth after they have been rayed into the soil from the Cosmos. (Steiner 2007:44)

STEINER, Rudolf. 2007. The Agriculture Course. (Trans.: George Adams) Shrewsbury: Wilding & Son Ltd.