The _Morochthus_, according to Sprengel, is called _Speckstein_ and _Seifenstein_ in German. It consists of talc, argil, and silica, with a small proportion of iron and manganese. Dr. Hill says it is an indurated clay, and is now known by the name of _French chalk_. Dioscorides recommends it in hæmoptysis, cæliac affections, and pains of the bladder; and for the cure of fluor albus on pessaries. (v, 151.) Avicenna speaks favorably of it also in fistula lachrymalis. (ii, 2, 431.) The _Achates_, or Agate, is well described by Orpheus, and recommended as a remedy for fever and various other complaints. It does not seem to be noticed by the medical authorities. The ancients were acquainted with several varieties of _Jasper_. See Pliny (H. N. xxxvii, 37.) They contained talc and various other ingredients. Dioscorides recommends it solely as a phylactery _or_ amulet to expedite delivery. (v, 159.) Galen and Avicenna speak of its being useful as an amulet in affections of the stomach and bowels. The latter calls it _Lapis aneseb_. (ii, 2, 408.) Even in modern times the Jasper has been celebrated as an amulet. See Andreas Laurentius (De Mirab. Strum. Sanat. 69), and Hill (Mat. Med. 276.) The _Judaic-stone_ appears to be the Tecolithos of Pliny. It is now ascertained that it is formed from the quills of the _Echinus Marinus_, impregnated with calcareous earth, silica, and perhaps some magnesia. Most of the ancient authorities commend it as a lithontriptic. V. Harduin in Plin. H. N. xxxvii, 68. Dioscorides recommends it not only as a lithontriptic medicine, but a remedy for dysuria in general. (v, 154.) Galen and Serapion also affirm that they had experienced good effects from it when given in calculus of the kidneys or bladder. See in particular Serapion (c. 390.) Rhases, however, affirms that he had tried the lapis vesicæ, by which he probably means this article, but had not found it to be lithontriptic. (Cont. l. ult. 414.) Dr. Hill says it is, undoubtedly, diuretic, but it is not so certain that it is lithontriptic. The _Pyrites_, when burnt, forms an oxide of copper with sulphur. From our author’s account, it is evident that the Molaris nearly resembled it, and the same may be understood from Pliny. It will, of course, be understood that it is the copper pyrites, and not the iron. This is very obvious from the description of it given by Dioscorides. He calls it heating, detergent, and a cleanser of obscurities of the eyes, and recommends it for repressing fungated ulcers. When burnt, he adds, some call it _diphryges_. It is described under the name of _marchasita_ by Serapion (c. 395), Phases (Cont. l. ult. i, 449), and Avicenna (ii, 2, 464.) They all recommend it with vinegar in leprosy and other obstinate diseases of the skin.