Officinal. Rhatany root, Galls, Uva Ursi, Tormentil, Rhubarb, Cinchona barks, Swietenia, Simarouba, Kino, Catechu, Willow bark.

12. Wax is a fixed oil: it consists of two distinct parts, one of which is termed Cerine, the other Myricine. (Part ii.)

13. Camphor. The ultimate components are carbon, hydrogen, and oxygen. (Part ii.)

14. Scillitina. This substance is procured from the bulb of the Squill. It is white, transparent, and pulverulent; has an intensely bitter taste, leaving a sweetish impression on the palate. It is soluble in water and alcohol, and when heated swells and exhales the odour of calomel. It is not a simple substance.

Officinal. The bulb of the Squill.

15. Quassina is the pure bitter of Quassia. Officinal. Quassia wood; Simarouba bark.

16. Daphnia, procured from the bark of the Daphne Mezereum.

Officinal. Bark of Spurge Laurel.

17. Nicotina is obtained from the leaves of several species of Nicotiana. It is colourless, acrid, and burning to the taste, and has the odour of tobacco; is soluble in water, alcohol, and ether; and approaches the volatile oils in its properties. It is extremely poisonous. It has an alkaline reaction, and forms crystallizable salts with acids. Officinal. Tobacco leaves.

18. Cathartina is the active purgative principle of Senna. It is uncrystallizable, of a reddish yellow colour; has a bitter nauseous taste, a peculiar odour; and becomes moist in the air. It is insoluble in ether, but soluble in alcohol and water in all proportions.

Officinal. Senna leaves.

19. Resins are brittle, semi-transparent, yellowish substances, inodorous, and having an acrid taste. Their specific gravity varies from 1.0452 to 1.2289. They melt when heated, inflame in a higher temperature, and burn with a strong yellow flame, emitting much smoke. They are insoluble in water; but soluble in alcohol, ether, alkalies, and acetic acid. Nitric acid converts them into artificial tannin.

Officinal. Amber, copal, pine resins, mastiche.

20. Guaiacum differs from resins in being soluble in nitric acid, and when treated with it, in yielding oxalic acid, and no tannin. (See Part ii.)

21. Hematina is the colouring matter of Logwood. It is procured in small brilliant crystals of a reddish white colour. Their taste is bitter, acrid, and slightly astringent. They form an orange red solution with boiling water: alkalies in excess change them first to purple, then to violet, and, lastly, to brown; and the hematina is decomposed. (See Part ii.)

Officinal. Logwood and its extract.

22. Emetina. This substance is obtained from Ipecacuanha and some other roots, which have an emetic property. It is, when pure, in the form of white scales, inodorous, but having a bitter and slightly acrid taste. It is not very soluble in water, but is readily dissolved in alcohol, and is soluble in acetic acid, and all the other acids, with which it forms salts. It is insoluble in ether. Nitric acid converts it into oxalic acid. Half a grain, when swallowed, excites full vomiting. It is a compound of 64.57 of carbon + 7.77 hydrogen + 4 nitrogen + 22.95 oxygen in 100 parts.1

Officinal. Ipecacuanha root.

23. Cinchonia, an alkaline salt, obtained from the bark of the Cinchona lancifolia and oblongifolia. It is inodorous, has little taste unless it be dissolved in alcohol; is white, translucent, and crystalline. It is scarcely soluble in water, ether, or oils, but is very soluble in alcohol. It unites with all the acids, and forms soluble salts. It is a compound of 122.4, or 20 eq. of carbon + 12, or 12 eq. of hydrogen + 14.5, or 1 eq. of nitrogen + 8, or 1 eq. of oxygen. Equivalent 156.55. (Part iii.)

1 To obtain Emetin, treat powder of Ipecacuanha, with ether at 63°, as long as it acts upon it: then boil the powder several times with fresh quantities of alcohol at 40°, and filter the boiling solutions, which will throw down as they cool a white flocculent precipitate : filter again, and evaporate the clear solution in a water bath. Dissolve the reddish residue which will be obtained in cold water, and add magnesia, which will precipitate the Emetin, that may be now obtained in a state of purity by dissolving the precipitate in alcohol, and evaporating the solution to dryness.

24. Quina, an alkaline salt procured from the bark of Cinchona cordifolia and oblongifolia. Inodorous, very bitter, white, little soluble in water, very soluble in ether. Combines with acids, and forms soluble salts. It consists of 122.4, or 20 eq. of carbon + 12, or 12 eq. of hydrogen + 14.15, or 1 = of nitrogen + 16, or 2 eq. of oxygen.

25. Salicina, a salt procured from the bark of the Salix Felix, Populus tremula, etc. It consists of 12.24, or 2 eq. carbon + 2, or 2 eq. of hydrogen + 8, or 1 eq. of oxygen.

26. Picrotoxa is procured from the fruit of the Menisper-mum cocculus, in white, four-sided, prismatic crystals; of an intensely bitter taste, soluble in twenty-five times their weight of water, and in three times their weight of alcohol and of ether. It is insoluble in oils. Nitric acid converts it into oxalic acid. It is intoxicating, and poisonous when swallowed. It consists of 61.434 of carbon + 6 of hydrogen + 32 426 of oxygen, = 100.00. Officinal. Cocculus Indicus.

27. Morphia. This is an alkaline substance procured from opium. It is in white pyramidal crystals, scarcely soluble in boiling water, but very soluble in alcohol and ether. It combines with the acids, forming neutral salts. It acts with great energy on the animal economy. (See Part ii.)

Officinal. Opium.

28. Aconita, an alkaline substance, procured from the Aconitum Napellus, on which the poisonous qualities of that plant are supposed to depend. (See Part ii.) Officinal. Aconitum Napellus and its extract.

29. Atropia, an alkaline substance, on which the poisonous and active properties of Belladonna depend. (See Part ii.)