Vegetables, as herbs and plants, or their fruit, seed, flowers, &c., which resemble some human member in figure, colour, quality, and consistence, were considered to be most adapted to that member, and to possess medical properties specially applicable to it. All herbs or plants that in flowers or juice bear a resemblance to one or other of the four humours, viz., blood, yellow bile, phlegm, and black bile, were deemed suitable for treating the same humour, by increasing or expelling it. All yellow-hued plants, if they were eatable, were thought to increase yellow bile. In this category were included Orach, Melons, Crocus, yellow Turnips, and all other yellow plants which have a sweet flavour. Plants or herbs of a dull blackish colour, or of a brownish or a spotted hue, were held to be serviceable in the treatment of black bile. Some of them had a tendency to increase it, while others assisted in carrying it off. Thus, Smilax, Mandragora, many kinds of Parsley, Nightshade, and Poppies, having partly black, ash-coloured, and spotted flowers, intermixed with pale tints, by causing bad dreams, excite giddiness, vertigo, and epilepsy. Napellus, also, indicates in a most marked manner its poisonous and virulent nature, for its flower represents the skull of a dead man. Plants which bear white flowers and have thick juice, which often grow in moist and extremely humid places, and which resemble phlegm or rheum, were thought to increase the very humours they represented. Others of a drier temperament were thought to correct and purify the same. Milky plants, as _Tithymallus_, _Polygala_, _Sonchus_, and _Britalzar Ægyptiaca_, were supposed to increase and accumulate milk in nurses. Some plants of a red colour were believed to increase blood; some to correct and purify it; and others to benefit hemorrhoidal and dysenteric affections from a similarity of colour. Plants of a mixed colour, as they unite in themselves a diversity of temperaments, were thought to produce a diversity of effects; whence two-coloured herbs were believed to possess and exercise a double virtue. On this principle, diverse colours were said to cure diverse humours in the human body; for example, _Tripolium_, _Panacæa_, and _Triphera_ were considered beneficial for all humours. Plants whose decoction and infusion, as well as colour and consistence, were like some humour of the human body, were declared to be appropriate for the purpose of evacuating that humour by attraction, or increasing it by incorporation.