A farther proof of the presence of lead in wines is the occurrence of a precipitate, on adding a solution of the sulphate of soda.
The most satisfactory proof, however, is derived by distilling off the alcohol, and calcining the residuum with charcoal, in order to obtain the metallic lead.
The quantity of lead which has been detected in sophisticated wine, may be estimated at forty grains of the metal in every fifty gallons,[393] but this will of course be liable to vary with the degree of acidity it was intended to correct.
3. The lead is dissolved in oils. In this case the lead may be detected by shaking, in a stopped phial, one part of the suspected oil, with two or three parts of water, impregnated with sulphuretted hydrogen. This test will announce the presence of the deleterious metal, by occasioning a dark brown, or black colour.
4. The lead is mixed with alimentary matter. M. Orfila has furnished us with the following directions for assaying the matter vomited, or that which may be found in the digestive canal, after death. “After having expressed the fluid portion through a piece of fine linen, it must be assayed by the tests, which have been already enumerated as being capable of detecting the salts of lead; and if the precipitates obtained are of a nature to induce a belief, that the fluid contains some preparation of this kind, it must be evaporated to dryness, and calcined with charcoal in a crucible; when, at the expiration of three quarters of an hour, metallic lead will be obtained. If all the experiments made on the fluid portion of the matter vomited, for the discovery of this poison, should be fruitless, the whole of the solid portions, previously dried, should then be calcined with potass and charcoal, by which means metallic lead will be obtained.”
The poisons of which we are about to offer the physiological and chemical history, although more numerous than those which belong to the mineral kingdom, are, notwithstanding, of far less importance in a forensic point of view. With the exception of opium, and some few others, they must be considered as objects of accidental, rather than of criminal poisoning; and even with respect to the former narcotic, it may be said to afford more frequently the means of destruction to the suicide, than to the assassin.
The sensible qualities of smell, taste, and sometimes colour, which so eminently characterise deleterious plants, must necessarily render them ill calculated to favour that secresy, which constitutes the indispensable companion of crime; while their bulk, and the pharmaceutical preparation which they require, are alike inconsistent with the hope of concealment.
Thus we receive, as it were, from Nature, that protection which art can no longer supply; and the commission of crime is either prevented or discovered, in cases where the powers of chemistry would fail in its detection.
The objects which constitute the vegetable kingdom differ from every species of mineral matter, not only in their peculiar organized structure, but in the chemical arrangement of their elements; those of inorganic matter are generally combined in very simple proportions, as one and one, or one and two, &c. whereas in organized bodies, their proportions are much more complicated; and Dr. Ure observes,[394] that such substances derive the peculiar delicacy of their chemical equilibrium, and the consequent facility with which it may be subverted and new modelled, to the multitude of atoms grouped together in a compound; hence too, as Mr. Children[395] has observed, is one reason of our utter inability to reproduce even the simplest body of this class, when once its elements have been separated; it is not in the diversity of these elements, but in the manner in which they are grouped, that this peculiarity consists, for, continues the accomplished chemist last mentioned, “vegetable substances seldom contain, as essential, more than three principles—oxygen, hydrogen, and carbon, and sometimes azote. With four simple elements then, a brief alphabet for so comprehensive a history! has a bountiful Omnipotence composed the beautiful volume of the living world, where, turn to what page we may, fresh loveliness meets the eye, fresh cause of admiration and delight.”
The analysis of vegetable bodies resolves itself into two parts, each of which constitutes an equal object of interest to the forensic physician; who, it will be shewn, may occasionally derive important information from both. The first relates to the discovery of the proximate principles of a vegetable substance. The second, to that of its ultimate elements. By the proximate, or, as they are sometimes termed, the immediate principles, we mean those compound substances which exist in the living plant in a state identical with that, under which chemical processes exhibit them, and are chiefly separable by the action of different solvents. The number of these principles is considerable, as gum, starch, sugar, gluten, extractiue, tannin, oils, acid, &c. &c. By the ultimate elements, we understand those, of which the proximate are composed, as oxygen, hydrogen, carbon, and azote. In submitting a plant to destructive analysis, for the purpose of obtaining its ultimate elements, we shall derive compounds, which formed no part of the vegetable structure, and which result from a new arrangement of the elements composing it; acetic and carbonic acids, for example, are obtained by the destructive distillation of several vegetable substances, in which neither of these acids existed ready formed, but only their elements.[396] It may easily be imagined to what numerous fallacies such a law of composition must have given origin, in the earlier periods of chemical inquiry; and it is equally evident, that the utmost refinement of chemical science, and the most rigorous methods of analysis, will be required to enable us to deduce any satisfactory conclusion with respect to the quality of a plant, from these data. Such perfection, indeed, has not hitherto been attained, but the period is probably not far distant, when our most sanguine anticipations upon this point may be realised. We have only to trace the history of this branch of chemistry for the last century, to become satisfied of its gradual and important progress towards such an epoch, and of the improvements of which this department of vegetable analysis is farther susceptible; let us, for the sake of illustration, only compare the rude results obtained by the academicians of Paris, at about the commencement of the seventeenth century, with those of MM. Gay-Lussac and Thenard[397], or with those, very lately instituted in this country by Dr. Ure,[398] and we shall perceive that while the former of these experimentalists, by the aid of heat, were unable to form the slightest distinction between the most inert, and the most poisonous species of plants, the latter, by means of the same agent, aided by the modern doctrine of equivalent ratios, has succeeded in establishing the proportions in which the elements of each vegetable body combines; and with such accuracy, as to discriminate between substances, which bear the greatest analogy to each other; as between the varieties of sugar, and those of oil; and even between common flax, and the same substance prepared according to the improved process of Mr. Lee. This statement is sufficient to show the capability of ultimate analysis, on certain occasions, to identify vegetable bodies; but we are, at present, scarcely advanced far enough in such an investigation, to make it subservient to the detection of vegetable poisons. Nor has our knowledge with regard to proximate analysis, been less successfully advanced. The late researches of the French and German chemists have demonstrated the existence of several new alkaline bodies in the class of vegetable poisons, to which some of these plants appear to be exclusively indebted for their activity, as the poppy, hellebore, colchicum, &c.; and whose characters are so distinct and striking, as to enable the chemist to recognise their presence by appropriate re-agents. In other cases, the virulence of a plant would appear to depend upon the combination of several[399] proximate principles; while in some few instances there exist in the same individual vegetable, two distinct elements of activity, as illustrated by the interesting history of tobacco.
In cases of vegetable poisoning it will occasionally occur, that some remains of the plant may be collected; and seeds, portions of the fungi, and leaves, may be found in the contents of the stomach; whence a knowledge of botany becomes indispensable. This branch of science is, moreover, important to the toxicologist, as enabling him to pursue the study of plants with greater precision; for experience has shewn that there is a wonderful analogy between the structure of those plants which resemble each other in medicinal operation. Thus those which, from their dismal and dusky appearance, have been arranged under the title of Luridæ, are in general highly poisonous; they also possess a very peculiar and disagreeable smell, so that Nature has, upon this occasion, kindly given us notice of approaching danger, by means of our senses.
Of equal importance with the knowledge of the generic and specific characters, is that of their sensible qualities, and the changes which these latter undergo by pharmaceutical preparation.
Most of the subjects of this class constitute articles of Materia Medica; so that ignorance on the one hand, and accident on the other, may render them the unexpected source of mischief. With respect to the physiological action of these bodies, the reader has only to refer to our classification at page 207, to perceive that it will not admit of generalization; for each division, it will be observed, contains individuals which belong to the class of acrid poisons.
As the history of most of these articles is to be found in works on Materia Medica, we shall not enter so fully into their properties, as we might otherwise have considered necessary.
This beautiful gum-resin is obtained by making incisions in the leaves and young sprouts of the Stalagmitis Cambogioides[400] (Polygamia Monæcia—Nat. ord. Tricoccæ. Wild:) It is first collected, in the kingdoms of Siam and Ceylon, in cocoa-nut shells, and is thence transferred into large earthen jars, where it remains until it is nearly dried to a cake, when it is formed into rolls, and wrapped up in leaves. It is imported into Europe[401] in cases and boxes. Its deep yellow colour, which is so materially brightened by being wetted, and its shining fracture, are characters sufficiently striking to enable the practitioner to identify it; and when we add to these the history of its habitudes with different menstrua, the chemist will have no difficulty in detecting its presence, viz. when triturated with water, two-thirds of its substance are speedily dissolved, and a turbid solution results; alcohol dissolves nine-tenths, and forms a yellow transparent tincture, which is rendered turbid by the addition of water; sulphuric ether dissolves six-tenths of the substance; it is also soluble in alkaline solutions, and the resulting compound is not rendered turbid by water, but is instantly decomposed by acids, and the precipitate so produced is of an extremely brilliant yellow colour, and soluble in an excess of acid.
Its action upon the animal œconomy is that of a powerfully drastic purge. We are, however, not acquainted with any case in which death followed its administration. From the experiments made upon animals, it would appear to produce its effects by a local action on the textures, with which it comes in contact, and it will accordingly be found in the third class of our physiological classification, (page 207.)
This is undoubtedly the true hellebore of the ancients. It is a native of the mountainous parts of Greece, Italy, Switzerland, and Russia. Those specimens which are cultivated in our gardens flower in July. The root is the only part employed in medicine, but every part of the plant is extremely acrid and poisonous. Upon the animal œconomy it acts as a violent cathartic and emetic; producing bloody stools, excessive vomitings, great anxiety, vertigo, tremors, sinking of the pulse, syncope, cold sweats, convulsions, and death. There are many cases on record, where such effects have followed the ingestion of this plant. Helmont reports that a royal prince died in the course of three hours after taking a scruple of this poison, which induced convulsions; and Vicat[403] relates the case of a tailor, his wife, children, and workmen, who having taken soup, in which, through mistake, the root of white hellebore had been introduced instead of pepper, were seized with a universal coldness, and such extreme debility, as to become nearly insensible. At the expiration of two hours, the eldest child, who was not four years of age, began to vomit copiously, but with considerable straining; the rest were shortly after in the same condition. Vicat, who was called in at this critical period, ordered them to take a considerable quantity of warm water and oil; shortly after which he administered an infusion of mallow sweetened with honey; by which means, we are informed, they were relieved, and ultimately restored. According to the testimony of various physiologists, as well as from the experiments of Orfila, it appears that this plant, if externally applied, will produce the same effects. Etmuller says, that the external application of the root to the abdomen will produce vomiting; and Schroeder observed the same phenomenon to take place in a case where it was used as a suppository; the juice of the plant has been also applied to the purpose of poisoning arrows. It must, therefore, act by being absorbed into the circulating current, thereby destroying the energy of the nervous system. It accordingly finds a place in the second division of our classification. Late experiments upon this substance have shewn that its activity depends upon a peculiar alkaline principle, to which the name of veratria[404] has been given; and that it exists in native combination with an excess of gallic acid, (super-gallate of veratria).
When taken internally, as a poison, the most effectual antidote is said to be a very strong infusion of nut-galls.
This plant, which has derived its name from the dark colour of the root, is a native of Austria, the Apennines, and Italy; it has, however, obtained a place in our gardens,[405] and from the circumstance of its flowering from December till March, it has acquired the name of the christmas rose. The fibres of the roots are the parts employed in medicine; their odour is fœtid, and their taste bitter and acrid. Its action upon the animal œconomy is similar to that of the preceding species. Morgagni relates the history of a person who took half a drachm of black hellebore, and expired eight hours afterwards. M. Orfila states that inflammation of the rectum is a constant occurrence, where the animals who have taken this root, have survived its administration for a few hours.
This plant is a native of England, growing in shady places, on a chalky soil, and flowering in March and April. Like the former species of hellebore, it is capable of producing fatal effects. A case is related in the London Chronicle, 1768, no. 1760, of a child who died in consequence of taking the root of this plant in the pulp of an apple.
This plant is a perennial native of the south of Europe, flowering in June and July; it is cultivated in England, but does not survive the severity of our winters. The fruit (poma) has the appearance of a small oval cucumber, of a greyish colour, and covered with prickles. When fully ripe it quits the peduncal, and casts out the seed and juice, with great force, and to a considerable distance, through the hole in the base where the foot-stalk is inserted, whence the name of squirting cucumber. The author has instituted numerous experiments upon this plant, the results of which will be found fully detailed, under its history, in the fifth edition of his Pharmacologia.
The plant appears, from the testimony of Dioscorides, and other writers, to have been employed by the ancient physicians with much confidence and success as a cathartic; all the parts of the plant were considered as purgative, although not in an equal degree; thus Geoffroy, “radicum vis cathartica major est quam foliorum, minor vero quam fructuum.” This question, however, has been very lately set at rest, by the valuable experiments of Dr. Clutterbuck,[406] which prove that the active principle of this plant resides more particularly in the juice which is lodged in the centre of the fruit. The forensic physician, however, will scarcely be liable to meet with a case of poisoning by the fruit of this plant. It is from that preparation of the juice, which is admitted into our Pharmacopœia, under the title of Extract of Elaterium, that we may expect to meet with mischief.
This substance subsides spontaneously from the juice of the fruit; and occurs in commerce in little thin cakes, or broken pieces, bearing the impression of the muslin upon which it is dried; its colour is greenish, its taste bitter, and somewhat acrid; and when tolerably pure it is light, pulverulent, and inflammable. Notwithstanding its extreme activity, it does not, according to our experiments,[407] contain more than a tenth part of active matter, which is a vegetable proximate principle, sui generis, and to which we have given the name of Elatin. By treating the Elaterium with alcohol, this principle may be obtained; it imparts to the spirit a most brilliant, and beautiful grass green colour—but see our experiments upon this subject. The action of elaterium is that of a most violent drastic cathartic, especially affecting the rectum. It destroys life by its local action, and consequently finds a place in the third division of our classification.
This is the fruit of the Cucumis Colocynthis (Monœcia Monodelphia, Nat. Ord. Cucurbitaceæ) an annual of Turkey and Nubia. It is of the size of an orange, of a yellowish-white colour, devoid of smell, round, dry, light, spongy, and smooth on the outside, when ripe; it is trilocular, each cell containing many ovate, compressed, whitish seeds, enveloped by a white spongy pulp. It is imported into this country, after having been peeled, and dried in a stove. Its taste is extremely bitter and acrimonious. It acts upon the human body as a powerfully drastic purgative. Fordyce,[408] relates the case of a woman who was subject to colics for the space of thirty years, in consequence of having taken an infusion of this fruit in beer. Tulpius[409] has also furnished us with an account of the tremendous effects produced by an overdose of the same article; and Orfila has shewn, with his usual accuracy, that it acts not only locally upon the primæ viæ, but by being absorbed, and carried into the circulation.
This gum resin is imported from Barbary, in drops, or irregular tears; its fracture is vitreous; it is inodorous, but yields a very acrid, burning impression on the tongue. Its acrid constituent resides exclusively in that portion which is soluble in alcohol. This poison has been sometimes administered imprudently as a purgative when it has produced vomiting, and bloody stools. Lamotte speaks of a clyster prepared with it, which proved fatal. It acts as a caustic upon the textures with which it comes in contact, and thus destroys life by a local action; indeed its nature is so acrid that when applied to the hair, or to warts, it causes them to fall off. Scopoli mentions the case of a person who, having the eye-lids closed, allowed them to be rubbed with the juice of this plant; in consequence of which inflammation followed, and the sight was lost. In pulverizing the gum-resin, the parmaceutist should take the precaution of previously moistening it with vinegar, or the powder will rise, excoriate his face, and excite violent inflammation of the eyes. There are many species[410] of Euphorbium, or spurge, which are highly poisonous; and, being indigenous, they have frequently proved the cause of mischief; during the last summer the author was consulted on the occasion of a family of children having been seized with a violent inflammation of the eyes, and eruption on the face, when the phenomenon was very satisfactorily traced to the action of the Euphorbia peplus, which was growing very luxuriantly in the garden where the children had been playing.
This shrub is a native of the south of Europe and the Levant; but has been long cultivated in our gardens. The leaves and tops of the plant have a strong, heavy, disagreeable odour, and a bitter, hot taste, with a considerable degree of pungency; qualities which depend upon the presence of an essential oil. Upon the animal system it acts as a very powerful stimulant, and has been received into the list of the materia medica, as an active emmenagogue; while it has long enjoyed, amongst the vulgar, the reputation of being capable of producing abortion.[411] Upon this point we have only to observe, that it does not exert any specific action on the uterus; but as a violent medicine, acting upon the general system, it might, in common with other stimulants, produce so much disturbance as to be followed by abortion. The experiments of Orfila have shewn that savine exerts a local action, but that its effects depend principally on its absorption, through which medium it acts on the nervous system, the rectum, and the stomach.
There are several species of aconite, all of which are poisonous. The monkshood is a well known plant, met with in our gardens, and when swallowed in any quantity will produce the symptoms, characteristic of vegetable poisons. All the parts of aconite, in the fresh state, when chewed, produce a sense of heat, and shortly afterwards a sensation of numbness in the lips and gums, which does not subside for several hours.
In ancient authors, we frequently meet with aconite as a poison, but it has been fairly questioned whether any particular plant was designated by the term[412]; like that of cicuta, it seems to have been a word expressive of poisons generally. The most powerful form in which this vegetable poison exists is in that of extract, or inspissated juice[413], and, if prepared according to the improved process of Mr. Barry,[414] it will prove highly dangerous in small doses. M. Orfila relates several fatal accidents from the ingestion of this plant; his experiments have also shewn that it will produce its effects by an external application. We agree, however, with Mr. Brodie in considering that it acts, without being absorbed, on the brain, through the medium of the nerves; and we have accordingly placed it in the first division of our classification.
The plants already enumerated are sufficient to illustrate the symptoms and physiological action of the acrid poisons of the vegetable kingdom. We shall, therefore, conclude the history of this class with some account of the nitrate of potass, which has been ranked both by Fodéré and Orfila under this division of their classification.
The sensible qualities of this salt are too well known to require any description. It generally occurs crystallized in six-sided prisms, terminated by dihedral summits. It is composed of one proportional of nitric acid, and one proportional of potass. It dissolves in seven parts of water at 60°, and in its own weight at 212° Fah. Its solution is attended with a great reduction of temperature. It is permanent in the air, melts when exposed to a moderate heat; and, when cast into moulds, constitutes what is known in commerce by the name of sal prunelle. When mixed with inflammable matter it undergoes, in a strong heat, a rapid species of combustion, which, in chemical language, is termed deflagration. Concentrated sulphuric acid, when poured upon this salt in powder, decomposes it at the ordinary temperature, and disengages vapours of nitric acid, which are white, and not very abundant.
This salt, when taken in a large dose, acts violently on the stomach and bowels, and occasions syncope and death. There are several cases recorded of its having been taken by mistake for Glauber’s salt.
On these occasions, the patients have been seized with violent vomiting and purging of blood, attended with severe pains in the bowels, and a sense of burning heat, referred to the chest and stomach; cold extremities, fluttering pulse, laborious breathing, syncope, and death. The above effects have been produced by an ounce and a half of nitre; although, as Dr. Gordon Smith has observed, the same quantity of this salt has been inadvertently swallowed without the production of such tremendous consequences.
From the experiments of Orfila, it appears that if this salt be inserted into a wound, it occasions a fatal gangrene. Its action is undoubtedly the effect of its acrid nature, destroying the vitality of the textures with which it comes in contact. It is not absorbed.
In those recorded cases of death from the ingestion of nitre, the stomach has been found red, scattered over with blackish spots, and its mucous membrane disorganized.
The property which this salt possesses of deflagrating with combustible bodies, affords a ready indication of its presence. The process also, which we have described under the history of nitric acid, (p. 312) as the one suggested by Dr. Wollaston, and adopted by Dr. Marcet in his examination of sea water, furnishes an elegant mode of ascertaining the presence of a nitric salt.
These constitute a class of vegetable poisons, less extensive, perhaps, but of far greater importance and interest, than the one we have already considered. It would not be easy to enumerate the various purposes to which the active imagination of man has applied the tribe of narcotic plants. Medicines, poisons, intoxication, and madness, lie concealed beneath their juices. They have, in their turn, arrested the pangs of disease, and inflicted death upon the unsuspecting object of hatred and revenge; they have animated the courage of the warrior, inspired the enthusiasm of the poet, soothed the sorrows of the wretched, and furnished the debauchee with a daily source of sensual gratification; effects which, although apparently incompatible with each other, may be commanded by the same substance, in a different dose. It would be foreign to the plan of this work to enter into a physiological inquiry into the modus operandi of these extraordinary agents; and the author relinquishes the labour with less regret, as he has already, in another work,[415] very fully considered the several theories which have been advanced for its explanation.
This well known drug is the inspissated juice of the Papaver Somniferum (Polyandria Monogynia. Nat. Ord. Rhoedææ, Linn. Papaveraceæ Juss.) obtained by making incisions in the half ripe capsules, at sun-set, when the night dews favour the exudation of the juice, which is collected in the morning by old women and children, who scrape it from off the wounds with a small iron scoop, and deposit the whole in an earthen pot, where it is worked by wooden spatulas in the sun-shine, until it attain a considerable degree of spissitude. It is then formed by the hand into cakes, which are laid in earthen basins to be further exsiccated.[416] Two kinds are found in commerce, distinguished by the names of Turkey, and East Indian opium. The latter kind is regarded as being inferior to the former.
Turkey opium occurs in flat pieces, of a solid compact texture, possessing considerable tenacity; its specific gravity is 1·336, so that, when compared with concrete juices of other plants, it is heavy, being exceeded only in this respect by opoponax and gum arabic. It is of a reddish-brown, or fawn-colour, and has a peculiar, heavy, and narcotic odour; its taste is acrid, bitter, and hot. By long exposure to the air, it becomes hard, and breaks with a glimmering fracture, owing to the presence of a few saline particles. It is plastic, and when worked with the fingers is adherent to them. When brought near a lighted candle it inflames, and burns with a brilliant light, but its odour at that time is not narcotic. It is partially soluble in water, alcohol, æther, wine, vinegar, and lemon-juice. When triturated with hot water, five parts in twelve are dissolved, six suspended, and one part remains perfectly insoluble, and resembles the gluten of wheat, but is of a dark colour. The alcoholic is more highly charged with its narcotic principle than the aqueous solution; but spirit, rather below proof, is its best menstruum.
Few vegetable substances have been more frequently, or more ably submitted to analysis; and the history of the successive steps by which our knowledge respecting its composition has advanced, must encourage us in hoping that we shall shortly be enabled to identify, by chemical tests, the presence of opium, with as little difficulty and as great precision as we are already capable of recognising a metallic poison.
According to the latest chemical views respecting the composition of this body, it may be stated to consist of the following principles, viz. resin, gum, bitter extractive, sulphate of lime, gluten, and the three lately discovered bodies, narcotine, morphia, and meconic acid.
In the year 1803, Derosne first obtained from opium a crystalline substance, which he found to dissolve in acids, but he does not appear to have instituted many experiments, for the elucidation of its nature and properties. In 1804 Seguin discovered another crystalline body, and although he described many of its properties, what appears very extraordinary, he never even hinted at its alkaline nature. Sertuerner, at Eimbeck in Hanover, had at the same time as Derosne and Seguin, obtained these crystalline bodies, but it was not until the year 1817, that he first proclaimed the existence of a vegetable alkali, and attributed to it the narcotic powers which distinguish the operation of opium; to this body, he gave the name of Morphia, and it would appear to be the same as the essential salt of Seguin. The salt of Derosne was also at first mistaken for the same principle, but the experiments of Robiquet have pointed out its distinctive properties, and it has received the name of Narcotine.
Morphia, upon which the soporific powers of opium depend, appears to exist in native combination with a peculiar acid, to which the name of meconic acid has been bestowed. The following are the essential characters of this alkaline body, when procured in a state of purity.[417]
It crystallizes in fine, transparent, truncated pyramids, the bases of which are either squares or rectangles, occasionally united base to base, and thereby forming octohedra. It is sparingly soluble in boiling water, but dissolves abundantly in heated alcohol, giving rise to an intensely bitter solution; in æther it is far less soluble. It has also the characters of an alkali; affecting test papers tinged with tumeric or violets, uniting with acids and forming neutral salts, and decomposing the compounds of acids with metallic oxides. It unites with sulphur by means of heat, but the combination is no sooner formed than it is decomposed. It fuses at a moderate temperature, when it resembles melted sulphur, and like that substance crystallizes on cooling; it is decomposed by distillation, yielding carbonate of ammonia, oil, and a black resinous residue, with a peculiar smell; when heated in contact with air, it inflames rapidly, and like vegetable matter, it leaves a carbonaceous residue. When analyzed by means of the deutoxide of copper, it yields carbon, hydrogen, and oxygen, the atomic proportions of which have not yet been ascertained. The nitric acid of commerce, when dropped on morphia, communicates to it a beautiful red colour. Sertuerner has given us an account of the effect of the alcoholic solution of morphia on himself, and three of his pupils; he found that repeated small doses of half a grain produced at first decided excitation; then weakness, numbness, and tendency to fainting; after swallowing vinegar while in this condition, violent vomiting was excited; in one delicate individual, profound sleep intervened, and on the following day he suffered from nausea, vomiting, head-ache, anorexia, constipation, and heaviness.[418] This case is sufficient to shew, that although morphia possesses the characteristic powers of opium, its strength is by no means commensurate with its supposed state of concentration. When uncombined, it exerts little or no action, in consequence of its insolubility in water, and in the fluids of the stomach. When, however, it is combined with an acid, particularly the acetic, or the meconic, with the latter of which we have before stated that it exists in opium, it displays its properties in a very eminent degree. It is also very soluble in oil; and, according to the experiments of M. Majendie, the compound acts with great intensity.
The meconic acid, when separated from the residuum of the magnesian salt, as described in the process for the preparation of morphia (note p. 386) does not appear to possess any medicinal activity. Its distinguishing chemical character is, that it produces an intensely red colour in solutions of iron, oxidized ad maximum; and a deep blue, with solutions of the salts of gold. Narcotine is the salt originally obtained by Derosne, and is supposed by MM. Majendie and Robiquet to be the peculiar principle which produces the excitement experienced by those who take small doses of opium. It may be entirely removed by macerating the extract of opium in sulphuric æther.
In considerable doses, the primary action of this substance, as a powerful and diffusible stimulant, is not apparent; for the powers of life are immediately depressed, drowsiness and stupor succeed, and these are followed by delirium, stertorous breathing, cold sweats, convulsions, and apoplectic death.
The quantity of opium necessary for the production of such effects must be regarded as relative. In no two cases can we ensure a similar result, by the administration of the same dose. But, of all the circumstances capable of modifying the power of this drug, habit is the most remarkable; in illustration of which we have only to adduce the history of the opium eater, or laudanum drinker; a species of debauchee by no means uncommon, as every London chemist can testify, for he frequently experiences considerable doubt and difficulty in distinguishing persons, to whom habit has rendered large doses of opium necessary, from such as purchase it with a view to suicide.[419] The lowest fatal dose, to those unaccustomed to it, seems to be about four grains; but the Turk will take three drachms in the morning, and repeat the same dose at night, without any other effects than that of cheerfulness and exhilaration. This temporary impunity, however, is dearly purchased by years of suffering and sorrow. The effects of opium, says Russel, on those who have been addicted to it, are at first obstinate costiveness, succeeded by diarrhœa and flatulence, with loss of appetite, and a sottish appearance; their memories soon fail, they become prematurely old, and then sink into the grave objects of scorn and pity.[420]
Where a person has, from accident, or design, swallowed a large dose of pure opium, or laudanum, the symptoms produced are so characteristic and striking, that the practitioner, who may be summoned to render assistance, will have no difficulty in ascertaining their cause.
Insensibility, with a scarcely perceptible respiration, although in some cases it is attended with an apopletic stertor; the countenance is livid and cadaverous; the skin cold; and the muscles of the limbs and trunk in a state of extreme relaxation. The pupils are insensible to the impression of light, and the pulse is almost imperceptible. In some stages, the patient, by being strongly shaken, may be roused for a few moments from the lethargy; there is generally a narcotic odour distinguishable in the breath. Vomiting may also take place upon the first impression of the laudanum upon the stomach; although after its action has been displayed upon the brain, it will be difficult to excite emesis by the most powerful means; the reason of which may be very satisfactorily deduced from the ingenious experiments of M. Majendie on the mechanism of vomiting; by which he proves, that without the influence of the brain, the muscles, whose actions constitute an essential part of the operation, are incapable of performing their duty, and that vomiting therefore cannot take place. This is a very important doctrine, inasmuch as it suggests to the pathologist several expedients, by which he may be enabled to occasion vomiting, by recalling the excitability of the brain. The period which will elapse, between the ingestion of the poison, and the death of the sufferer, may be stated to be from six to twenty-four hours; but it will in each case be liable to vary, not only from the quantity of opium swallowed, but from the habit and peculiar circumstances of the individual submitted to its operation.
It is still a question for the decision of future physiologists, whether the narcotic principle of opium destroys the functions of the nervous system by a local impression upon the stomach,[421] or by being absorbed,[422] and brought into contact with the brain in the course of the circulation. We are inclined to adopt this latter opinion, and have therefore placed opium in the second division of our classification; at the same time, we think that it may occasionally produce an effect upon the nervous extremities of the stomach, and we have accordingly placed an asterisk against the word, by which we denote this double mode of operation. But, by whatever medium it may act, it is evident that it occasions death by destroying the functions of the brain; in consequence of which the muscles of respiration, no longer supplied with nervous energy, cease to contract, and the animal dies in a state of suffocation.[423]
The first object is the evacuation of the stomach by vomiting; for which purpose, the patient should be made to swallow from fifteen grains to a scruple of sulphate of zinc; or, from five to ten grains of sulphate of copper dissolved in water; and the vomiting should be kept up for a considerable time, and urged by irritation of the fauces. Where the act of vomiting cannot be established, in consequence of the paralysed state of the nervous system, cold affusion, applied by means of a shower bath, has been said to restore the energy of the brain, and thus to render the patient susceptible of the stimulus of an emetic.[424] Venesection has also, under the same circumstances, been greatly extolled; and, as vascular congestion in the brain is one of the effects of this poison, it is reasonable to conclude that, by unloading the vessels of this organ, we may restore its lost sensibility. Tissot has strongly recommended the practice,[425] and the experiments of Orfila have shewn that it never aggravated the symptoms of poisoning by opium, nor accelerated the moment of death; but on the contrary, that in some instances he found that it restored the animals which would have died, if it had not been put in practice. Where the operation is performed, the blood should be drawn from the jugular vein, in preference to any other. Should these means prove insufficient to provoke vomiting, M. Orfila asks, whether one or two grains of tartarized antimony, dissolved in one or two ounces of water, might not be injected into the veins? It was formerly proposed by Boerhaave to empty the stomach of its poisonous contents, by the introduction of a syringe; an operation which, it is said, has been lately performed with success.[426] Vinegar and vegetable acids were long considered as antidotes to opium; but the experiments of M. Orfila have clearly established that, as long as any portion of the opium remains in the stomach, these potations, so far from relieving, aggravate the symptoms of poisoning by this narcotic, in consequence of the power which they possess of dissolving it. Where, however, the opium has been expelled by vomiting, these acid drinks possess the property of diminishing the consecutive symptoms, and of thus realising the expectations which Virgil[427] has so poetically raised,