A L O

ALO ( 45 )

the solution is reCent this reagent only slightlydisturbs it.

Spirit of wine dissolves aloes with greatease when warm. The solution is of a verydeep red, and water added to it gives a copiouspale yellow sediment. If the spirituous solu-tion is much lessened by evaporation, theslightest agitation causes the surface to assume acrystalline form.

IN either the fixed nor the essential oils dis-solve any sensible portion of aloes.

All the alkalies dissolve aloes very easilyeven without heat, and the intense bitter issomewhat corrected in this solution.

The ammoniacai solution carefully evapo-rated almost to dryness, gave the author anumber of needled crystals impacted in a re-siniform mass. These crystals gave the smellof ammonia when rubbed with lime and mois-tened, and hence this alkali appears to be oneof their component parts.

"Weak acids merely dissolve aloes, and some-what more abundantly than water does.

Nitric acid dissolves it easily in the cold,producing a blood-red liquid, precipitable bywater. A quantity of aloes was put into aretort and heated cautiously with eight partsof strong nitric acid. Abundance of nitrousgas was given out, and when this action hadceased the retort contained a yellow liquid,which on cooling deposited a good deal of ayellow flocculent substance, that weighed afterwashing on the filter about a quarter of theweight of the aloes employed. The author con-siders this as an acid possessing some peculiarproperties, and terms it the Aloetic. Acid. It isof a very fine yellow and intensely bitter, notcrystallizahle, reddens litmus, and effervesceswith the alkaline carbonates. Its smell is agree-ably aromatic when warmed. It is very slightlysoluble in water, and the solution has thecolour of arterial blood. Alcohol dissolvesonly -jV of its weight of this acid. Themineral acids merely dissolve without decom-posing it. Potash forms a red crystallizahlesalt with this acid, which detonates with theviolence of gunpowder when heated sufficientlyor touched with an ignited body. The salt iseasily produced by pouring a weak solution ofcaustic potash on the yellow aloetic acid.

The liquor that remains after the extractionof this acid from the heated mixture of aloesand nitric acid, contains also much oxalic acid,*o as to give a copious precipitate of oxalate oflime on the addition of nitrat of lime.

M.- Braconnot infers from his experiments,that the chief constituent part of aloes isneither a gum nor resin, but a substance saigeneris , which he terms Bitter Resin (Resiiio-Amer.)

IvI. TrornvnsdorfT’ has given a comparativeanalysis of the Socotrine and Hepatic aloes, d ofwhich a few particulars may be mentioned.Four ounces of aloes were boiled with 3 pintsof distilled water. The whole dissolved, butbecame very turbid on cooling, and a yellowsubstance separated, weighing an ounce afterdrying. This substance was a bitter, yellow,brittle, transparent resin, fusible at a gentleheat, insoluble in water, very soluble in alcoholand potash, and highly inflammable.

The liquor that contained that part of thealoes which remained soluble in water, wasevaporated to dryness, and gave a brown bittermass equally soluble in water and alcohol, blitinsoluble in ether, which the author considersas identical with what Ilermbstaedt terms theSaponaceous Principle of vegetables. Ano-ther portion of aloes was analyzed by firstdigesting it in alcohol, in which it totallydissolved without any residue but a few grainsof woody impurity. The solution remainedclear after cooling. After being evaporatedto dryness, the residue was digested with water,and only three fourths of it dissolved, leavingone fourth of resin; which confirmed the gen-eral proportion of resin and other matter foundin the first experiment.

Some difference was found in the subsequentanalysis of the Hepatic aloes, this speciescontaining about fth of albumen which resistedsolution in boiling water and in alcohol, owingto its coagulation. This therefore is given asa mode of distinguishing the two species; theSocotrine aloes dissolves entirely in boilingwater and in alcohol, but the Hepatic when thustreated, leaves a portion of coagulated albu-men.

Further experiments have been made uponaloes by Messrs. B. La Grange and Vogel, ewith some slight difference as to results.

A portion of each kind of aloes was distilledper se. Some water and oil passed over, theformer of which gave a brownish-black colourto sulphate of iron, but this tinge did notresemble that produced by the distilled waterof the gall nut; neither was the water of thealoes at all altered in colour by lime, baryticor strontian-water, all of which give a blue,green, or rose-colour precipitate with thesec An. Cli. torn. 68.

i An. Ch. tom. 68.