M. M. Pelletier and Caventou have discovered in this substance, a peculiar proximate principle, to which its virulence is owing; it was named Vauqueline, in honour of the celebrated French philosopher, but in deference to the opinion of the French Academy of Sciences, the discoverers have substituted the name Strychnia, because “a name dearly loved, ought not to be applied to a noxious principle!”[[569]] (Annales de Chimie, vol. 8 to 10.) Strychnia is highly alkaline, and crystallizes in very small four-sided prisms, terminated by four-sided pyramids; its taste is insupportably bitter, leaving a slight metallic flavour, and is so powerful as even to be perceptible when a grain is dissolved in eighty pounds of water;[[570]] it has no smell; is not changed by exposure to the air, nor is it either fusible or volatile, for when submitted to the action of heat, it only fuses at the moment of its decomposition which takes place at a temperature inferior to that which destroys most vegetable substances; it is so extremely active and violent, that in doses of half a grain it occasions serious effects, and in larger ones convulsions and death; it is perhaps the most powerful,[[571]] and next to hydro-cyanic acid, the most rapid of poisons; notwithstanding its strong taste, it is very sparingly soluble in water, requiring 6667 parts of that fluid for its solution at 50, and 2500 at 212°. It is very soluble in alcohol, but unlike most of the other vegetable alkalies, is nearly insoluble in æther; with acids it forms neutral and crystallizable salts; these salts as well as their base, have the singular property of becoming bloodred by the action of concentrated nitric acid. The alcoholic solution of Strychnia has the property of precipitating the greater number of metallic oxides from their acid solutions. It is precipitated by alkalies and alkaline earths. Strychnia exists in native combination in the Strychnus with an acid which has some analogy with the malic, and which Pelletier and Caventou propose to call the Igasuric acid, from the Malay name for the bean of St. Ignatius,[[572]] (Strychnus Ignatius,) in which its properties were first examined. In conformity with such views, the active principle of the tribe of Strychni is an Igasurate of Strychnia;—a fact which suggests the existence of a most singular and striking analogy between the chemical constitution of these narcotico-acrid bodies[[573]] and that of opium. The recent experiments of Pelletier have shewn, moreover, that besides Strychnia, the Nux Vomica contains Brucia, an alkaline body which had been previously discovered in spurious Angustura. Its properties are similar to those of Strychnia, but it is less active. Being much more soluble in alcohol than Strychnia, if care be taken to crystallize the latter several times in alcohol, it will be separated, the Brucia remaining in the mother waters. Strychnia has been given in doses of one-twelfth of a grain, but it is a most dangerous remedy, and is liable to occasion tetanic convulsions.[[574]] It has been said, however, to prove serviceable in cases of Epilepsy that had resisted every other method of cure. Dr. Fleming informs us that the Hindoos of upper India are in the habit of adding Nux Vomica in the process of distilling Arrack, for the purpose of rendering the spirit more intoxicating. The London Porter brewers have been accused of the same pernicious practice.
OLEA DESTILLATA. L. Ol. Volatilia. E.
Ol. Essentialia. D.
Distilled, Volatile, or Essential Oils.
The British pharmacopœiæ direct them to be obtained by distillation only; the French codex orders several of them to be prepared by expression. Qualities. Form, liquid, sometimes viscid; specific grav. various; oil of turpentine, which is the lightest, being only 0·792, whilst the oil of cloves, cinnamon, and allspice, exceed 1·030, and that of sassafras, which is the heaviest, amounts to 1·094; these latter oils hold resin in solution, and of course sink in water. Odour, penetrating and fragrant; Taste, acrid; they are volatilized at a temperature somewhat below that of boiling water; they are very inflammable. Solubility. Very soluble in alcohol, forming what are termed in perfumery Essences; in water they are very sparingly soluble; the solutions are known in pharmacy under the title of distilled waters; they are also dissolved by æther, and the fixed oils; when digested with ammonia, some of the less odorous acquire a considerable degree of fragrance, whilst on the contrary, fixed alkalies universally impair their odour; they are rapidly decomposed by nitric and sulphuric acids, and their action is sometimes attended with instant inflammation. Volatile oils, from continued exposure to the air, absorb oxygen, and become resinous, by which they lose their volatility, fragrance, and pungency, hence they should be preserved in small opaque phials, completely full and well stopped. Med. Uses. They act as powerful stimulants and aromatics; they remove nausea and flatulence, correct the griping of certain purgatives, and cover the offensive taste of various remedies. See Aquæ destillatæ. They, moreover, have the property of defending certain animal and vegetable preparations from mouldiness. This curious fact has been already noticed, see page 177. The following is a list of the species admitted into our British pharmacopœiæ; those designated in italics are principally for internal use. Olea Anisi, Anthemidis, Carui, Juniperi. Lavandulæ, Menthæ Piperitæ, Menthæ viridis, Origani, Pimentæ, Pulegii, Rosmarini, L. Olea Volatilia, Juniperi communis, Juniperi Sabinæ, Lavandulæ Spicæ, Lauri Sassafras, Menthæ Piperitæ, Myrtæ Pimentæ, Pimpinellæ Anisi, Rorismarini Officinalis. E. Olea Juniperi, Pimento, Corticis et Ligni Sassafras, e Seminibus Anisi, Carui, Fœniculi dulcis, Florum Lavendulæ, Foliorum Sabinæ, Herbæ florescentis Menthæ Sativæ, Origani, Pulegii, Rorismarini, Rutæ, D. Adulterations. Fixed Oils may be detected by moistening writing paper with the suspected article and holding it before the fire: if the oil be entirely essential, no stain of grease will remain; as castor oil is more soluble in spirit than the others, it is the one generally selected for this fraudulent purpose, and the addition of alcohol restores the sophisticated oil to its proper degree of consistency. Alcohol is discovered by adding water, which, if it be present, occasions a milkiness, and at the same time, an increase of temperature; a decrease of bulk also takes place, which may easily be ascertained by measuring the oil and water separately, and then transferring them, in a state of mixture, into a tube of small diameter. Cheaper oils, as that of turpentine, are recognised by their peculiar odour, which may be developed by rubbing a drop upon the hand and holding it to the fire, or, by the dense black smoke with which they burn. The oil of aniseed, as it crystallizes at 50°, is frequently sophisticated with wax, spermaceti, or camphor; the fraud is detected by warming the oil, when the crystals, if genuine, will dissolve.[[575]] In some cases the refractive power of the oil affords a test of its purity. See my work on Chemistry in its relations to Medicine, § 318.
OLEA EXPRESSA. L.D.
Olea Fixa, sive Expressa. E.
Expressed or Fixed Oils.
These are obtained from animal matter by fusion, and from vegetable by expression, or decoction with water. Qualities. Odour, none; Taste, mild; they boil at 600°, but undergo decomposition, becoming acrid and empyreumatic; the oil, in this state, was formerly used in medicine under the name of philosopher’s oil.[[576]] By exposure to air they absorb oxygen and become rancid; they congeal at a temperature of 32°, and some even above that. When the oil is expressed by heating the plates of the press, or by previously roasting the seeds, it is more disposed to become rancid; cold drawn oils are on this account to be preferred for the purposes of pharmacy. Solubility. They are insoluble in water, and, except castor oil, nearly so in alcohol and æther; with caustic alkalies they combine and form soaps; when aided by heat they readily unite with oxide of lead, forming the solid compound well known by the term plaister. They unite also very readily with each other, and with volatile oils. Solvent Powers. They dissolve sulphur, and form a kind of balsam with it; they also possess the power of extracting and dissolving the narcotic and acrid principles of several vegetable and animal substances, in consequence of which, the French pharmacopœia directs a series of preparations under the term “Olea Medicata;” thus there are olea Cicutæ, Hyoscyami, Solani, Stramonii, Nicotianæ;[[577]] which are made by digesting with a gentle heat, one part of the subject in two parts of olive oil.[[578]]
OLEUM AMYGDALARUM. L.E.D.