As many truths not yet investigated by means of new experiments, and which on that account have not yet been acknowledged, are concealed among the evidently false assertions to be found in the works of the ancients, and as these works were thrown aside too early, before their contents were properly examined, I was induced to suspect that some hints of this colouring property might also be mentioned in them, which indeed is the case. We learn from the works of Galen and Dioscorides, that the ancient physicians remarked that the use of certain roots, which they administered to their patients, communicated a colour to their urine and excrements; and this observation has been repeated by Cardan, Thurneisser, Porta, Castor, Durantes, and others. Had those ancient physicians, who often prescribed these roots, and paid attention to the colour of the excrements of their patients, been accustomed to open their bodies when they died under their hands, they would have perhaps remarked, in human bones, what was observed long after in the bones of animals, when the roots were no longer used in medicine; and what, if I am not mistaken, was never yet observed in the bones of the human species[279]. Böhmer, who made researches respecting the antiquity of this observation, found it neither in Rombert. Dodonæus, Mich. Ettmuller, Morin, Will. Salmon, nor others, who, however, speak of coloured urine. In his opinion the oldest writer who speaks of coloured bones is Mizaldus; but what he relates is all taken from the treatise of Lemnius De Miraculis Occultis Naturæ; and the latter therefore is the oldest writer that I at present can mention as acquainted with this property. He was a physician in Zealand, where madder has been cultivated since the earliest ages, and where he had an opportunity of remarking it. He says that the bones of animals became red, as had been observed when the flesh was dressed, by their eating only the leaves, and not the roots. In the first edition of the above work, printed in octavo, in the year 1559, which consists of two books, this information will not be found; but it may be contained in the second of 1564, which comprehends four books. [The madder plant is much cultivated in Holland, but Macquei observes that the Dutch were first indebted to the Flemish refugees for their knowledge of the method of preparing this plant. Its culture has often been attempted in England, but always without success[280]. It is also largely cultivated in Alsace and Provence in France, especially near Avignon, in Asiatic Turkey, and in Italy; from which places it is largely exported. The Turkey and Provence madder is procured from _Rubia peregrina_; the remainder from _R. tinctorum_. To prepare the root, which is the part used in dyeing, it is removed from the ground, picked, dried and ground. Madder contains three distinct colouring principles; two of these are red, viz. alizarine and purpurine, and one, xanthine, is yellow.