SPERMACETI. WAX. PARAFFINE.

203. Spermaceti, CHO2, identified.

Characteristic pearly crystalline appearance.

159

Fuses in

water heated to 120° F. (49° C.). (See 194a.) Boiling with potash does not saponify it. Does not evolve the pungent vapors of acroleine when heated, thus. differing from palmitine.

204. Wax identified.

27 54

(See 194a). When the solu

White or yellow; not distinctly crystalline. Fuses in water heated to 145° or 150° F. (63° or 66° C.). Boiled with alcohol, is partly dissolved. tion cools, cerotic acid, CH,,O,, crystallizes out, which fuses in water heated to 174° F. (79° C.). The alcoholic solution reddens litmus. When evaporated on a water bath, it leaves ceroleine, a greasy substance of peculiar odor, fusible at 83° F. (28° C.). Wax is little affected by boiling with potash. 205. Paraffine identified.

White. Crystalline; resembles spermaceti. Fuses in water heated to 112° F. (44° C.).* (See 194a). Very sparingly soluble in alcohol. Unaffected by boiling with potash. May be distilled with little decomposition, which is not the case with wax.

206. The commonest organic substances which are insoluble in boiling water, alcohol, and ether, and which cannot be distinguished by their organized structure,† are

Albumen and Caseine, in their coagulated or insoluble states, so nearly resemble each other, that no satisfactory test can be given by which they may be distinguished.

They are both white and opaque in the moist state, becoming horny, yellowish, and translucent when dried.

* Some specimens of paraffine fuse at 1490 F. (650 C.).

Such substances as fibrin, cellulose, lignine, hair, silk, wool, horn, &c., would always be recognized without having recourse to chemical tests.

Dried albumen and caseine, placed in water, slowly soften, swell, and become white and opaque.

Heated in a tube, they carbonize, swell up, and emit very offensive vapors, which are strongly alkaline to reddened litmus paper.

Strong nitric acid colors them bright orange, and gradually dissolves them when heated.

Solution of nitrate of mercury, prepared by dissolving 2 parts of mercury in 4 parts of nitric acid (sp. gr. 1.40) imparts a bright red color to albumen and caseine (Millon's test).

Potash dissolves albumen and caseine, when heated; acetic acid, gradually added to the solution, causes a flocculent precipitate, which is redissolved by an excess of the acid.

If albumen or caseine be boiled with potash, and a few drops of solution of acetate of lead, a dark precipitate of sulphide of lead is produced.

Strong hydrochloric acid slowly dissolves albumen and caseine with the aid of heat, yielding solutions which have a violet color.

LIQUID ORGANIC SUBSTANCES.

2. LIQUID ORGANIC SUBSTANCES.

TABLE Q.

NOTES TO TABLE Q.

208. The commonest liquid organic substances (not distinguishable by the preceding Tables) which have a distinct color, and mix easily with water, are—

Alcohol
Aldehyde
Aceton

Wood-spirit (methylic alcohol)
Nicotine

Butyric acid.

209. Alcohol, C2HO, or Spirit of Wine (which is a mixture of alcohol and water), may often be recognized at once by its odor.

If not too much diluted, it inflames readily, and burns with a pale flame.

If much water be present, it may be separated either by carbonate of potash (226), or by distillation (227).

When alcohol, even in a diluted state, is mixed with enough chromate or bichromate of potash to color it distinctly, a little hydrochloric acid added, and heat applied, the red color of the solution is changed to green, in consequence of the reduction of the chromic acid to chromic oxide by the deoxidizing effect of the alcohol, a part of which is converted into aldehyde, distinguishable by its peculiar odor.

By heating alcohol with some strong sulphuric acid, and an acetate (either acetate of potash, soda, or lead), the very agreeable odor of acetic ether is developed.

210. Methylated-spirit (a mixture of spirit of wine with wood-spirit) may be distinguished from pure spirit of wine by its odor, and by the brown red color which it assumes when mixed with strong sulphuric acid.

211. Wood Naphtha, CH,O (pyroligneous ether, pyroxylic spirit), is not commonly met with in commerce in a pure state, in which form it bears much resemblance to ordinary alcohol. The ordinary wood-naphtha has a yellowish color and a peculiar nauseous odor. When mixed with water,

WOOD-SPIRIT.

ALDEHYDE.

NICOTINE.

163

it becomes turbid, from the separation of certain oily im

purities.

Wood-naphtha burns with a pale flame, resembling that of

alcohol.

Potash immediately imparts a brown color to woodnaphtha, an effect not produced with alcohol until some time has elapsed.

212. Acetone, C,HO (wood-spirit), may be recognized by its peculiar odor (which may be ascertained by heating solid acetate of lead in a small tube). It differs also from alcohol and wood-naphtha by burning with a very luminous flame.

213. Aldehyde, CHO, has a very peculiar acrid applelike smell which affects the eyes. When exposed to the air it passes off in vapor much more readily than alcohol, woodnaphtha, or acetone, first becoming acid from absorption of oxygen.

If aldehyde be added to nitrate of silver mixed with a very little ammonia, the metal is reduced on the application of heat, and forms a mirror-like coating upon the side of the tube. Potash imparts a brown color to aldehyde. Aldehyde is very inflammable, and burns with a pale flame.

10 14 2

214. Nicotine, C1H1N,, is an oily liquid, tinged brown by exposure to air, and having a powerful odor of tobacco.

Its aqueous solution is strongly alkaline to test-papers. When the aqueous solution is acidulated with hydrochloric acid, mixed with bichloride of platinum, and allowed to stand, it deposits a precipitate composed of very distinct prismatic crystals.

Nicotine is inflammable, and burns with a smoky flame.

4 7

215. Butyric Acid HC,H,O,, is a colorless liquid, having a most powerful smell of rancid butter. It is somewhat lighter than water, in which it dissolves when shaken. If strong hydrochloric acid be added to the aqueous solution, the butyric acid separates again as an oil upon the surface.