Lac contains more resin and less coloring and nitrogenous matter. Shell Lac is about 90 per cent. resins, 5 per cent. wax, 2.5 per cent. gluten, and 0.5 per cent. coloring. The coloring matter of lac is soluble in water; is bright red with acids and deep violet with alkalies; is precipitated by alum.

Shell Lac is insoluble in water; soluble in alcohol; mostly soluble in methylic alcohol; wholly soluble in aqueous alkalies, and in water solution of borax, and in hydrochloric and acetie acids.-Lac resin is separated from most other resins, and from many natural and commercial impurities, by dissolving in a solution of part borax and 20 to 30 parts water to one part of lac. The solution may be diluted farther. (Good shell lac leaves not over 1.5 per cent. residue; poor, as much as 8 per cent.) By 10 per cent. ammonia at 25° to 30° C. lac is not dissolved, while Colophony dissolves and appears, after acidulation, as a precipitate. Cold ether (of 0.720 spec. grav.) does not dissolve more than 5 to 6 per cent., chloroform not over 7 per cent. from good lac, the dissolved part being wax with a very little resin (separation from Colophony and other resins).

90. MASTIC. A translucent solid, brittle and inodorous at ordinary temperatures, but soft and ductile when chewed and fragrant when heated, of a faintly terebinthinate taste. Alcohol dissolves about four-fifths, leaving Masticin undissolved. Ether, chloroform, and oil of turpentine dissolve it wholly. It is largely soluble in benzole.

Consists of resins, about

91. MYRRH Resin. part; gums, about part; with a very little soluble extractive. Myrrh forms an emulsion and partial solution with water, a nearly complete solution with much aqueous potassa, and yields its resin to alcohol, ether, and chloroform.-The Resin of Myrrh is readily soluble in alcohol, ether, chloroform; slightly soluble in hot solution of sodic carbonate; about one-half part soluble in bisulphide of carbon. That part extracted with bisulphide of carbon, when dissolved in alcohol and warmed with 25 per cent. nitric acid, gives a violet color.

92. OLIBANUM Resin. Frankincense. Incense.-Olibanum is about one-half part resin, one-third part gum, one-twelfth part volatile oil. The gum is soluble in water; the resin is soluble in alcohol.

93. Resin of PERU Balsam. About resins, volatile oil, less than cinnamic acid. The Balsam is of thick-syrupy consistence; spec. grav. 1.15 (sinks in an 18 per cent. solution of common salt). Soluble in absolute alcohol in all proportions, or in 6 parts of 90 per cent. alcohol with slight turbidity; perfectly soluble in all proportions of absolute ether, chloroform, and amylic alcohol. Bisulphide of carbon dissolves the greater part; benzole and petroleum naphtha dissolve about one-half. It mixes with about part of castor oil, and with part copaiba balsam. Sulphuric acid converts the balsam into a thick red mass. Aqueous alkalies dissolve out the resin. sam requires over 0.7 grams crystallized sodic trallize its cinnamic acid.

10.0 of the balcarbonate to neu

Insoluble

94. PODOPHILLUM RESIN. Consists of two resins. in water; wholly soluble in alcohol; about part soluble in ether; wholly soluble in aqueous alkalies, from which solutions acids precipitate it (distinction from resins of Jalap and Scammony). Insoluble in benzole.

95. SANDARAC. A brittle, yellow solid. Contains three resins. Sandarac is insoluble in water; wholly soluble in alcohol-part dissolving easily in cold ordinary alcohol, a small part requiring boiling alcohol, and a still smaller part a large quantity of this solvent for solution. It is easily soluble in ether and in oil of turpentine, imperfectly soluble in bisulphide of carbon, benzole, petroleum naphtha, or linseed oil. Nitric acid colors it clear brown.

96. SCAMMONY Resin. Convolvulin. See Jalapin (87).

97. Resinous part of STORAX. Consists of (two) resins, and Styracin or Cinnamate of Cinnyl (C,H,C,H,O,). Alcohol and ether dissolve the whole. In cold alcohol, the styracin crystallizes in tufts of prisms. Styracin is tasteless and odorless, more

freely soluble in ether than in alcohol. Treated with hot nitric acid, or with chromic acid, or with sulphuric acid and binoxide of manganese, it yields benzoyl hydride (oil of bitter almonds).

98. Resins of TOLU Balsam. The Balsam consists of 80 to 90 per cent. of resin, about 12 per cent. of cinnamic acid, and less than 1 per cent. of volatile oil. It is wholly soluble in alcohol, chloroform, volatile oils, and aqueous alkalies; partly soluble in ether; insoluble in benzole, petroleum naphtha, bisulphide of carbon, and solution of carbonate of sodium. The Resins of Tolu balsam are soluble in cold concentrated sulphuric acid, without change.

99. Separation of Resins by Solvents. Recapitulation. -Water dissolves a part of the resin of Assafetida, a part of Gamboge, about of Guaiac resin, and slightly dissolves Jalapin.

a. Alcohol fails to dissolve Caoutchouc, a part of Copal, solving slightly with heat), and

of Amber, Canatba wax, of Guaiacum, Indigo blue (disof Mastic.

b. Aqueous Alkalies (potassa or soda) dissolve Aloes resin, Amber, Ammoniac, Assafetida (mostly), Benzoin, Colophony, Convolvulin (with change), Dammara (Australian), Dragon's Blood (mostly), Guaiacum, Jalapin (with change), Lac resin, Myrrh, and resins of Podophyllum and of Peru and Tolu balsams.-These solvents do not dissolve Canaüba wax, Caoutchouc, Copal, Dammara (East Indian), Hemp resin, Indigo blue.

c. Ether dissolves resin of Aloes, Ammoniac (in part), Assafetida resin (mostly), Benzoin (in part), Canauba wax (with difficulty), Caoutchouc (mostly), Colophony, Copal (with difficulty), Dammara (in part), Dragon's Blood, Gamboge, Guaiacum (in greater part), Hemp resin (Cannabin), Jalapin, Mastic, resin of Peru balsam, of Podophyllum resin, Sandarac, Styracin, and resin of Tolu balsam.-Ether does not dissolve Amber, Indigo, and of Podophyllum resin.

d. Chloroform dissolves Caoutchouc, Colophony, Gamboge, Guaiacum, Hemp resin (Cannabin), Jalapin, Mastic, Myrrh,

resin of Peru balsam, resin of Senna, resin of Tolu balsam. -Chloroform does not dissolve Agaric (in chief part), resin of Aloes, resin of Colocynth, Convolvulin.

e. Bisulphide of Carbon dissolves Canauba wax, Caoutchouc, Copal (slowly), Dammara, Gamboge, Hemp resin, of Myrrh, resin of Peru balsam, Sandarac (in part).-It does not dissolve Amber, Indigo blue, & of Myrrh, resin of Tolu balsam.

f. Benzole dissolves Caoutchouc, Colophony, Dammara, Gamboge, Jalapin, Mastic (mostly), of the resins of Peru balsam, Sandarac (in part). Benzole does not dissolve Amber, Guaiacum, resin of Podophyllum, resin of Tolu balsam.

g. Oil of Turpentine dissolves Ammoniac, Benzoin resin (in part), Canaüba wax, Caoutchouc, Colophony, Copal (slowly), Dammara, Dragon's Blood, Guaiacum (mostly), Hemp resin, Jalapin, Mastic, Sandarac, resin of Tolu balsam.-It does not dissolve Amber, Indigo (without heating).

h. Sulphuric Acid, concentrated, cold, dissolves Amber (with red color), Ammoniac, Benzoin resin, Convolvulin (with red color turning brown), Copal, Dammara (with red color), Gamboge (with red color), Guaiacum (with red color, etc.), Indigo blue. It does not dissolve Caoutchouc.

100. VOLATILE OILS. In composition, 1st, IIydrocarbons, or "elæoptenes," mostly of the formula (CH)n, a large class;

2d, Oxidized oils (C, H, O), including (1) hydrates of hydrocarbons, the "stearoptenes" or camphors, a moderate number being found alone and a large number in mixtures with the elæoptenes, (2) aldehydes, (3) compound ethers, generally in natural mixture with elæoptenes, (4) of irregular composition;

3d, Sulphurized oils (C, H, O, S), a small class, products of natural fermentation, and having odors resembling each other.

101. Mostly liquids, a few oils and stearoptene parts of oils melting at a little above ordinary temperature; the greater number lighter, a few heavier, than water; very slowly volatile

at ordinary temperatures, mostly having boiling points above 150° C., but all distilling, slowly, with steam at 100° C., and leaving a transient oil-spot on paper. They are noted for strong and persistent odors; colorless, or with pale colors, in a few instances tinted blue with coerulein, transparent and possessed of strong refractive powers.-The volatile oils are neutral in reaction; not generally liable to decomposition or combination except with oxygen. By air and light many of them alter and form resinous bodies; the elæoptenes forming stearoptenes, and (by oxidizing agents) aldehydes forming acids.

102. Volatile oils are very sparingly soluble in water, requiring intimate mixture and generally from 600 to 1,000 parts of water for solution; soluble in alcohol, and in all proportions of absolute alcohol, ether, chloroform, benzole, petroleum naphtha, bisulphide of carbon, fixed oils and other volatile oils. Alkalies do not affect them.-Certain oils, after distillation with water, retain traces of water in solution. This occurs with oils of bergamot, cinnamon, cloves, juniper, lavender, lemon, rosemary, sassafras, spike, wintergreen; not with oils of amber, cedar, rue, turpentine. The presence of water is shown by turbidity on mixture with several volumes of petroleum naphtha (LEUCHS).— Volatile oils are scarcely at all soluble in aqueous solutions of chloride, nitrate or sulphate of sodium.

103. The volatile oils are characterized by their individual odors, their physical properties (as stated above and in 105 and 106), by various special reactions (the most of which are stated in 107 to 114), by their refractive indices and their absorption spectra, and by their cohesion-figures when dropped upon a still surface of pure water.*

104. Volatile Oils are separated from substances more or less volatile by their distillation with steam; from many substances by their slight solubility in water (farther lessened by

* TOMLINSON, MOFFAT: Chem. News, 1869. CRANE: Am. Jour. Phar., 1874, Sept., and Phar. Jour., 1874, p. 242, et. seq.