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Chap. I.

Properties.

Castor oil (oleum ricini) is distilled over in a retort, and the product of the distillation is boiled with water to free it from a portion of acetic acid, and to get rid of a volatile oil with which it is mixed. The portion remaining is a mixture of ricinic and elaiodic acids. Of this mixture one-third part is to be distilled over. This portion becomes solid at the temperature of 50°. It is to be subjected to pressure between folds of bloating paper which will imbibe elaiodic acid, with which it is still contaminated. It is now ricinic acid in a state of purity.

Ricinic acid thus prepared is a white solid having a pearly lustre. At 72° it melts into a colourless oil which assumes a crystalline texture on cooling. It may be volatilized in a retort by a moderate heat without decomposition. It has a strong and sharp taste. It is insoluble in water, but soluble in alcohol and ether. These solutions redden litmus paper. Its constituents when in crystals, as determined by the analysis of Bussy and Lecanu, are as follows:

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Composition.

Salts.

It would appear from the experiments of the same chemists, that ricinate of magnesia is composed of

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This makes its atomic weight 25. The number of atoms corresponding best with these two analyses is the following:

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But new researches are wanting to enable us to determine how near these proportions approach to the true atomic weight of the anhydrous acid; analogy leads to the conclusion that the crystallized ricinic acid contains an atom of water.

Ricinic acid when assisted by heat decomposes the alkaline carbonates. Ricinate of potash resembles soap. It is soluble in water and alcohol. It is decomposed by calcareous salts and also by common salt. The ricinate of soda resembles that of potash. Ricinate of lime is insoluble in water.

Rici

nate of magnesia is insoluble in water; but very soluble in alcohol. The same character applies to ricinate of lead and to several other ricinates.

SECTION XXXV.-OF ELAIODIC ACID.

This acid was also discovered by MM. Bussy and Lecanu during their researches on castor oil: but its properties have been very superficially examined. It may be obtained by the following process:

The castor oil is to be distilled and treated as described in the last section, till a mixture of ricinic and elaiodic acid is obtained as there stated. This mixture is to be cooled to 32°, and then subjected to pressure between folds of bloating paper. The ricinic acid remains while the elaiodic acid is imbibed by the paper. It is to be dissolved in alcohol, and freed from the small quantity of ricinic acid which it contains, by repeated evaporations and crystallizations.

Class I.

Div. II.

Elaiodie acid is a yellow coloured oil, congealing into a solid Properties. mass when cooled down a few degrees below 32°. It has a sharp taste, and has a slight empyreumatic smell. It combines easily with bases. The elaiodates of potash and soda dissolve readily in water and alcohol. Those of magnesia and lead are insoluble in water, but easily soluble in alcohol.

This acid is insoluble in water; but dissolves with facility in alcohol and ether.+

SECTION XXXVI.-
- -OF CEVADIC ACID.

This acid was discovered in the seeds of the veratrum saba- History. dilla, called cevadille by Pelletier and Caventou during their examination of that vegetable substance in the year 1820.‡ It was obtained by them in the following manner :

The seeds of the veratrum were macerated in ether, the action of which was assisted by heat. The ether when drawn off had assumed a yellow colour. This liquid being distilled by the heat of a water bath, the water passed off colourless and left a yellow unctuous matter, insoluble in water and soluble in alcohol and ether. It reddened vegetable blues, and had a strong and peculiar odour. To determine its nature it was converted into a soap by boiling it with potash ley. This soap was decomposed by adding to it an excess of tartaric acid. Flocks of unctuous matter separated which were composed of oleic and

* Jour. de Pharmacie, xiii. 68.

+ Ibid. 70.

+ Ibid. vi. 353.

Chap. I.

Properties.

History,

tartaric acids. The filtered liquid had a yellow colour, together with an acrid and acid taste. When subjected to distillation there came over an aqueous liquid having an acid taste and a strong smell, while cream of tartar and various other vegetable principles remained in the retort. Into the liquid thus obtained barytes water was poured, which destroyed the acidity of the liquid without entirely removing the smell. Being evaporated to dryness a substance was obtained of a fine white colour, composed of cevadic acid united to barytes. A sufficient quantity of phosphoric acid was added to saturate the barytes, and a gentle heat being applied, the cevadic acid sublimed, and was thus obtained in a separate state.

It

Cevadic acid thus obtained, is a solid substance of a fine white colour, and crystallized in needles. It melts when heated to the temperature of 68°. Its smell has a good deal of resemblance to that of butyric acid; but is not quite the same. sublimes at a moderate heat. It is soluble in water, alcohol, and ether. It combines with the different bases and forms a genus of salts called ceradates, which have been very imperfectly investigated. They retain a portion of the peculiar smell which distinguishes the acid.

This acid approaches nearest to the butyric and phocenie ; but is sufficiently distinguished by the concrete state in which it exists at temperatures below 68°.

SECTION XXXVII.—OF CROTONIC ACID.

*

This acid was discovered by Pelletier and Caventou about the year 1819, during their examination of what they considered as the seeds of the Iatropha Curcas, but which were afterwards found to be the fruit of the croton tiglium, a tree which grows in the Moluccas, and which yields croton oil, so much employed of late years in this country as a purgative. It is a very poisonous oil, which had been much employed by medical men during the 17th century, but which had gone out of use in consequence of the uncertainty of its operation, and the fatal effects which it produced when given in too large doses. To obtain crotonic acid, the croton seeds are digested in ether or alcohol. The infusion being distilled leaves a combination of oil and crotonic acid. This oily matter being boiled with water and magnesia to dryness and digested in ether, the oil is removed, and there remains a combination of crotonic acid and magnesia,

Jour. de Pharmacie, iv. 289.

which being mixed with phosphoric acid, and distilled, crotonic acid passes over.

But by this process very little crotonic acid is obtained, because most of it remains united to the oil. The best way of proceeding, therefore, is to convert the oil into a soap by boiling it with potash ley. The soap is to be decomposed by tartaric acid, the liquid is to be filtered and distilled in a well luted apparatus. The liquid that passes over, and which contains the crotonic acid, is to be neutralized with barytes water, and evaporated to dryness. The crotonate of barytes being now mixed with highly concentrated phosphoric acid and distilled, the crotonic acid is sublimed.

Class I.

Div. II.

Crotonic acid thus obtained congeals when cooled down to Properties, 23°. When heated a few degrees above 32° it sublimes in a vapour, having a strong smell, and acting pretty strongly on the nostrils and eyes. It reddens litmus paper. The taste is sharp, and its properties are very poisonous. It dissolves in water, alcohol, and ether. It is doubtless this substance which gives to croton oil its cathartic and poisonous qualities.

Crotonate of potash crystallizes in rhomboidal prisms, which are not altered by exposure to the air. It dissolves with difficulty in alcohol of the specific gravity 0.85. Crotonate of barytes is soluble in water, and when the solution is evaporated, either forms pearly crystals, or falls in the state of a white powder. Crotonate of magnesia may be obtained in small grains very little soluble in water. Crotonate of ammonia precipitates iron from the sulphate of an isabella yellow colour. It precipitates the salts of lead, copper, and silver white.

SECTION XXXVIII.—OF AMBREIC ACID.

Ambergris is a substance found floating in the sea, most History. commonly near the coasts of India, Africa, and Brazil, usually in small pieces, but sometimes in masses of 50 or 100 pounds weight. It is generally considered as a concretion formed in the intestines of the physeter macrocephalus, or spermaceti whale. It is a soft substance, which swims in water, having an ash gray colour with brownish yellow and white streaks. It was examined in considerable detail by Bouillon La Grange.* He extracted from it, by means of alcohol, a white substance, to which he gave the name of adipocire, because he considered it as the same with the substance which makes its appearance

* Ann. de Chim. xlvii. 73.

Chap. I.

Properties.

when dead bodies in great numbers putrefy together, and to which the name adipocire had been given by Foureroy. But being examined in 1820 by Pelletier and Caventou, they found reason to consider it as a peculiar substance, different from every other. On that account they distinguished it by the name of ambreine.*

Ambreine is easily obtained by digesting ambergris in hot alcohol, of the specific gravity 0-827, filtering the liquid, and leaving it to itself. The ambreine is deposited in a kind of stalactitical state, retaining a great deal of alcohol, which may be driven off by evaporation, when the bulk of the ambreine is very much diminished. It has a fine white colour, is tasteless, and has at first a sweet smell, which is dissipated by repeated crystallizations. It is insoluble in water, but dissolves readily in ether and alcohol of the temperature of 50°. It does not redden litmus paper. It melts at 862. When heated above 2122 it becomes brown, exhales a white smoke, and is partly decomposed. The white smoke consists of ambreine unaltered. It is incapable of forming soap with alkalies.

Pelletier and Caventou found that when treated with nitric acid and heat it dissolves and swells, while abundance of deutoxide of azote is driven off. The ambreine becomes first green and then yellow. It is now converted into a peculiar acid, to which Pelletier and Caventou, the discoverers, have given the name of ambreic acid.

To obtain this acid we have only to heat ambreine with nitric acid till it ceases to undergo any farther change. Then evaporate cautiously to dryness; wash the dry mass with cold water to remove as much of the acid as possible, then boil it with a little carbonate of lead. If we now wash it with cold water till the solution ceases to retain any traces of lead, we are certain that the nitric acid has been completely removed. We have only now to digest the residue in alcohol and set the solution aside; the ambreic acid crystallizes in small plates.

Ambreic acid when in masses is yellow, when much divided it appears white. white. It has a peculiar smell, quite different from that of ambergris. It reddens litmus paper. When heated, it is decomposed without furnishing any ammonia. It remains solid when heated to 212°, while cholesteric acid fuses at 136°. This constitutes a striking distinction between them.

Ambreic acid is also much less soluble than cholesteric in

* Jour. de Pharmacie, vi. 49.

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