During the winter the sap is thick, sweet, and albuminous; but in summer time it is bitter and acrid. Frost causes the bitterness to diminish, and sweetness to take its place; but after the frost this bitterness returns, and is intensified. The root is at its best for yielding juice about November. Chemically the active ingredients of the herb are taraxacin, and taraxacerine, with inulin (a sort of sugar), gluten, gum, albumen, potash, and an odorous resin, which is commonly supposed to stimulate the liver, and the biliary organs. Probably this reputed virtue was assigned at first to the plant largely on the doctrine of signatures, because of its bright yellow flowers of a bilious hue. But skilled medical provers who have experimentally tested the toxical effects of the Dandelion plant have found it to produce, when taken in excess, troublesome indigestion, characterized by a tongue coated with a white skin which peels off in patches, leaving a raw surface, whilst the kidneys become unusually active, with profuse night sweats and an itching nettle rash. For these several symptoms when occurring of themselves, a combination of the decoction, and the medicinal tincture will be invariably curative. To make a decoction of the root, one part of this dried, and sliced, should be gently boiled for fifteen minutes in twenty parts of water, and strained off when cool. It may be sweetened with brown sugar, or honey, if unpalatable when taken alone, several teacupfuls being given during the day. Dandelion roots as collected for the market are often adulterated with those of the common Hawkbit (_Leontodon hispidus_); but these are more tough and do not give out any milky juice. [150] The tops of the roots dug out of the ground, with the tufts of the leaves remaining thereon, and blanched by being covered in the earth as they grow, if gathered in the spring, are justly esteemed as an excellent vernal salad. It was with this homely fare the good wise Hecate entertained Theseus, as we read in Evelyn's _Acetaria_. Bergius says he has seen intractable cases of liver congestion cured, after many other remedies had failed, by the patients taking daily for some months, a broth made from Dandelion roots stewed in boiling water, with leaves of Sorrel, and the yelk of an egg; though (he adds) they swallowed at the same time cream of tartar to keep their bodies open.