middle region generally hangs down. This form grows on sunny slopes in bushes and thickets or on entirely exposed dry situations. f. angustifolia (Murr.). Grows, like the preceding, in sunny situations, but the leaves are comparatively narrow and lanceolate, more hairy and thicker. f. robusta (Gross). Leaves unusually large, 10–15 cm long, and over 5 cm. broad. Seeds 4–5 mm long. Plants very much taller and more robust, sometimes attaining a height of about 60–65 cm. Generally found under old oak or beech in fairly damp and shady localities. f. saxicola (Beck.). Leaves elongate-elliptic, 4-5 times as long as broad, gradually tapering towards the apex. Both the upper and lower faces of the leaves hairier. Generally on exposed chalky hills. f. variegata (Mukerji). Its leaves possess beautiful mottled patches of yellow and white, and by continued cultivation, this may be further improved. Chemical characteristics All parts of the dog's mercury are highly poisonous. Methylamine (mercurialine) and trimethylamine are thought to be present, together with a volatile basic oil, mercurialine, and saponins. The scent of the plant is often described as 'foetid' due to the presence of trimethylamine which often gives off a rotting fish smell. Mercurialine is thought to be one of the active principle parts that are responsible for the toxicity of the herb. It is known to induce hemorrhagic inflammation of the gastrointestinal tract and kidneys. There is apparently some narcotic action, which induces drowsiness, and mild muscular spasms. One hypothesized mechanism of toxicity was discovered in 1900s. A researcher induced toxicity with dog's mercury, frozen at different stages of growth and fed it to sheep. Based on this experiment, these effects may be due to different toxic factors that are developed at different growth stages. Another hypothesis is that one toxin might be culpable for the symptoms and illness. Symptoms of poisoning Symptoms of poisoning appear within a few hours; they can include vomiting, pain, gastric and kidney inflammation, and sometimes inflammation of the cheeks and jaw ("malar erythema") and drowsiness. Larger doses cause lethargy, jaundice, painful urination, apparently by making the urine acid, and coma before death. Reported cases of poisonings The first-known account of this phenomenon probably dates from 1693, when a family of five became seriously ill as a result of eating the plant (after boiling and frying it); one of the children died some days later as a result. Apart from Chenopodium bonus-henricus