The _Lapis Specularis_ was the same as the Moscovy talc. It was much used by the ancients for windows in place of glass. It is a variety of selenite, or sparry gypsum. See Kidd and Jameson. We have treated of it under the head of Gypsum in the Fifth Book. The _Smaragdus_ of the ancients is unquestionably referable to our emerald, but there is every reason to believe, also comprehended coloured crystals and certain stones of the jasper kind. It does not occur in the works of Dioscorides or Galen; and, as far as we know, Aëtius is the first medical author who describes it. He says of it, that when roasted and levigated with Attic honey, it cures dimness of vision; that it is most useful in elephantiasis, both externally and internally; and that as an amulet it restrains bleeding. (ii, 39.) We are not aware that any other ancient authority, whether Greek, Roman, or Arabian, has noticed it. We will treat of the _Bezoar-stone_ and _Gall-stone_ of the bull in the Appendix to this section. Λιθόσπερμον (called also λειόσπορμον ἢ ἡράκλειον), Lithospermon, _Gromwel_, is the seed of the herb called Aegonychus, of a stony hardness, and white, which, when drunk with white wine, proves lithontriptic and diuretic. * * * * * COMMENTARY. Without doubt it is the _Lithospermum officinale_, or _Gromwel_. Pliny expresses himself respecting it in the following terms: “Nec quidquam inter herbas majore quidem miraculo aspexi. Tantus est decor, velut aurificum arte alternis inter folia candicantibus margaritis: tam exquisita difficultas lapidis ex herba nascentis.” (H. N. xxvii, 74.) Dioscorides describes it minutely, and, like our author, calls it lithontriptic and diuretic. (iii, 148.) Serapion and Avicenna give it the same characters, which it maintained in modern times, as long as it held a place in the Dispensatory. See the works of Parkinson, Culpeper, and Quincy. Λινόσπερμον, Lini Semen, _Linseed_, is heating in the first order, and holds the middle rank of diluents and desiccants. When eaten, it is flatulent, even although roasted. * * * * * COMMENTARY. It is the seed of the _Linum usitatissimum_, Angl. _Linseed_. Dioscorides gives a long account of its medicinal virtues, recommending it externally for ephelides, vari, and other complaints, and internally as an expectorant and aphrodisiacal medicine. He further commends it as an enema in pains of the bowels and womb, and as a hip-bath in inflammations of the uterus. (ii, 125.) Galen, like our author, treats of it in very general terms. The Arabians, and especially Avicenna, give a more circumstantial account of it. (ii, 2, 598.) See Serapion (c. 21); Rhases (Cont. l. ult. 426.) Like Dioscorides, they recommend it as an external application to apostemes of a hard character, and internally for the cure of diseases of the chest and intestines. Λινόζωστις,