[563]. Essence of Peppermint.—A spirituous solution of the Essential Oil, coloured green by Spinach leaves.
[564]. If the Gum arabic be adulterated with that of the Cherry-tree, the solution will be ropy, in consequence of the presence of Cerasin. See Mucilago Tragacanthæ. (Note.)
[565]. The mucilage is at the same time converted by this salt into a beautiful peach blossom colour.
[566]. This variety of gum, which is characterised by its gelatinizing, but not dissolving, in water, occurs in several vegetable substances; and as it predominates in the Cherry-tree, Dr. John has distinguished it by the name of Cerasin; but as Tragacanth consists almost entirely of this substance, the term Tragacanthin would have been much more appropriate. Although Cerasin will not dissolve in pure water, it undergoes solution in that menstruum, at the temperature of ebullition, provided a portion of a mineral acid be added.
[567]. Sir Hans Sloane published a Paper in the Philosophical Transactions, No. 249, Vol. xxi. p. 44, entitled “An account of the Nux Pepita, or St. Ignatius’s Bean (Ignatia Amara, Lin.) A Simple in common use in the Philippine Islands, as a Tonic medicine.”
[568]. That the active principle of the Nux Vomica expends its virulence upon the spinal marrow has been already noticed. Page 133.
[569]. M. Henry has given us the most simple formula for the preparation of this substance. It consists in boiling Nux Vomica in water, and evaporating the decoction until it acquires the consistence of Syrup; lime is then added, which unites with the acid, and liberates the Strychnia; which may then be separated by means of alcohol, from which it may be obtained by crystallization.
[570]. Ann: de Chimie et de Phys. x. 153.
[571]. M. Majendie has killed a dog with one eighth of a grain, and the editor of the Edinburgh Med: & Surg: journ: has seen one die in two minutes after the injection of one sixth of a grain into the cavity of the pleura. The celebrated Java poison owes its activity to Strychnia.
[572]. Strychnia was obtained from the beans of St. Ignatius by the following process: a portion of the beans being grated was heated in a close vessel, under pressure, with sulphuric æther, by which an oily matter was dissolved; the residuum then yielded by the action of alcohol, a yellowish brown, very bitter substance, which being boiled in pure magnesia and filtered, the colouring matter was washed out, and the Strychnia and magnesia, in a state of mixture, remained on the filtre. The Strychnia was then separated by alcohol, and thus obtained in a state of great purity.