205. I have in my possession a splendid specimen of this triple salt, in large and well defined crystals, covering a portion of a decayed beam; it was sent to me by my friend Mr. Marshall, from whom I learnt that it had been taken from a privy belonging to a public house in Southwark. I lent the specimen to the late Mr. Wilson, in order that he might exhibit it in his lectures before the College of Surgeons, and he has published a description of it in his work on the Urinary and Genital Organs.
206. A question has arisen respecting the comparative efficacy of the two fixed alkalies upon these occasions. See Sodæ Sub-carbonas.
207. For an account of the celebrated remedy of Mrs. Stephens, see Liquor Calcis.
208. Journal de Physiologie; Juillet, 1823.
209. For a farther account of this extraordinary law of Electro-Chemistry, the reader may consult my work on the Elements of Medical Chemistry.
210. These experiments have been repeated at the Jardin des Plantes, with similar results; it farther appears that a certain quantity of Nitrate of Potass added to the water injected into the bladder will expedite the decomposition.
211. This, it must be confessed, is singularly unfortunate, if the opinion already expressed be true (page 121) viz. that at least two-thirds of the whole number of calculi originate from this acid.
212. The word Antidote is derived from αντὶ, against, and διδωμὶ, I give; as being a medicine given against poison, either by way of cure or preservative. The word is also sometimes used in a more general sense, for any compounded medicine; thus Peter Damian speaks of a person who in his whole life never took an antidote. It is likewise used by some authors in a less proper sense, for any remedy against any disease, chiefly if it be inveterate, and arise from some ulcer or abscess; and lastly, the term has been used to signify a perpetual form of medicines, otherwise called Opiates, or more properly Confections.
213. The reader will find this subject treated more fully in the second volume of my work on Medical Jurisprudence.
214. See the history of Theriaca at page 28 note.
215. John, king of Castille, as Tissot relates, was poisoned by a pair of boots, prepared by a Turk; Henry IV, by gloves; Louis XIV fearing a project to poison Philip V, prohibited his opening letters, or putting on gloves (Tissot Traité des Nerfs, T. 1. P. 11. page 13;) Plouquet has the following remark upon this subject, “Huc et ignota illa venena pertinent, quibus epistolæ chirothecæ, et ejusmodi infici, et vim adeo toxicam induere dicuntur, ut lectio ejusmodi epistolæ, indutus chirothecæ subitam mortem causentur.” (Comment. Med. super Homicid. page 184.) Pope Clement VII is said by Zacchias to have been poisoned by the fumes of a taper, (Quæst. Med. Leg.); and a priest is reported to have offered to destroy Queen Elizabeth by poisoning her saddle. (Sir Edward Coke, in the trial of Sir John Hollis.) Bishop Burnet, in the history of his own times (vol. 2. p. 230.) says, that some believed Charles the Second to have been poisoned through the medium of snuff.
216. This conceit does not appear to have been confined to the ignorant alone, for we learn from Spratt’s History of the Royal Society, that very shortly after the institution of that learned body, a series of questions was drawn up by their direction, for the purpose of being submitted to the Chinese and Indians, which clearly shews their belief in the possibility of such an operation, viz. “Whether the Indians can so prepare that stupifying herb, Datura, that they make it lie several days, months, years, according as they will have it, in a man’s body, without doing him any hurt, and at the end kill him without missing half an hour’s time?”
217. Dr. Mead adopted this opinion, but he became so convinced of its inadequacy that, in the later editions of his work on Poisons, he withdrew the hypothesis. It is hardly necessary to observe that upon its abandonment, a host of popular antidotes at once fell into disuse; for as long as the injury was supposed to arise from mechanical irritation, oils, fats, and other similar remedies were held capable of obtunding the acrimony. So has the abandonment of other conceits and hypotheses cleared away many absurd articles from the list of Antidotes; see page 26.
218. The introduction of poisons into the body through the medium of the circulation of the blood is frequently alluded to by the physiologists of the seventeenth century. I have lately met with a curious passage in a work entitled “Popular Errours in Physick, first written in Latine by the learned physitian, James Penrose, Doctor in Physick. London, 1651.” “The venome is carried by the veines and arteries, as appeares in that all the blood of them that have been bitten by a viper doth turne into a pale greennesse. And seeing that the veines in the papps are so very slender, and doe not come unto the heart, but with a great many long windings, I affirme, and it is more probable, that if the viper be applyed to the feet, which are farthest remote from the heart, it will sooner infect the heart than if to the papps, but soonest of all if it be applied to the armes. And now the story of Cleopatra comes to my minde. Petrus Victorius blames the painters, that paint Cleopatra applying the aspe to her papps, seeing it is manifest out of Plutarch in the life of Antonius, and out of Plinie likewise, that she applyed it to her arme. Zonaras relates that there appeared no signe of death upon her, save two blew spots on her arme. Cæsar also in her statue which he carryed in triumph, applyed the aspe to her arme; for in the armes there are great veines and arteries, which doe quickly, and in a straight way convey the venome to the heart, whereas in the papps the vessels are slender. And therefore in Saint Paul the miracle was so much the greater, in that he felt no harme from the viper, which layd hold on his hand, for if it had assailed him on the breast, he had had respite enough to take some antidote.”
219. There can be no doubt but that death has been produced by the mechanical operation of various insoluble bodies; although we cannot believe the numerous tales recorded on the subject of diamond dust (supposed to constitute the basis of the celebrated “Powder of Succession”) or of powdered glass, &c. Numerous cases are recorded where life has been destroyed by the lodgement of substances in the intestines; and we have lately heard of the fatal effects produced by alvine accumulations from the habitual use of Magnesia. With respect to the danger from the ingestion of glass and enamel in powder, there still exists much difference of opinion; Caldani, Mandruzzato, and M. Le Sauvage, report experiments made upon men and animals, in which no bad consequences followed; on the other hand, Schurigius (Chylologia) and Cardanus (De Venenis) cite instances where persons have died of ulcerations of the stomach from such causes; and M. Portal, Foderé, (Medicine Legale) Plouquet (Comment. super Homicid.) Stoll, (Ratio Medendi, part vi. p. 60) Gmelin (Hist. General de Ven. mineral.) Frank (Man. de Toxicol.) furnish testimony in support of the opinion which assigns to such bodies a highly deleterious action.
220. This mark denotes that the substance, against which it is placed, may also act by being absorbed.
221. Signifies that the article has also a local action.
222. See “Experiments and Operations on the Different Modes in which Death is produced by certain Vegetable Poisons.” By B. C. Brodie, Esq. F. R. S. in the 181st Volume of the Philosophical Transactions for the year 1811.
223. M. ’Lallemand has published the history of a fœtus, in which the brain and spinal marrow were equally deficient, notwithstanding which, it even exceeded the usual size, the heart was also perfect, and it was evident that the circulation had been properly performed. No sooner however was the monster born than it perished, because the diaphragm and other muscles of respiration were unable to perform their functions without the aid of nervous excitement; no air was therefore inhaled into the lungs, and in a few minutes the heart ceased to contract from the deficient supply of oxygenized blood. See Medical Jurisprudence, Vol. ii. “On the Physiological Causes, and Phœnomena of Sudden Death.”
224. It is a very curious fact, that the Oil of Tobacco should differ so essentially in its physiological action from the Infusion of that vegetable poison; the former we have stated, affects the brain only, the latter we now learn, when taken into the alimentary canal, suspends the action of the heart. This apparent anomaly at first led Mr. Brodie, as he has since informed me, to suspect the accuracy of his experiments: and I suggested to him, whether a probable explanation might not be derived from the late chemical researches into the composition of tobacco, which have shewn the existence of two active principles, viz. Nicotin, and an Essential Oil? Where an infusion is employed, we seem to obtain the influence of the former, and the effects are displayed upon the heart; but where the oil is applied, the Nicotin has been removed, and the brain is the organ principally affected—see Tabaci Folia.
225. Dry Vomit of Marriott. This once celebrated vomit, called Dry, from its being exhibited without drink, consisted of equal proportions of Tartarized Antimony and Sulphate of Copper.
226. Sydenham relates a case of poisoning by Corrosive Sublimate; which was successfully treated by copious draughts of water, and repeated vomiting (Opera Medica, Epist. 1, p. 200); and Orfila, in his laborious work on poisons, presents us with a mass of satisfactory evidence upon the same subject.
227. Circumstances, however, may occur, which will render it even judicious, with certain precautions, to administer a solvent, in order to remove the particles of the substance, which sometimes adhere with such obstinacy to the coats of the stomach as to defy the exertions of an emetic to detach them, especially if the poison be arsenic; but let the practitioner remember that this practice can never be allowed until all that can be ejected by vomiting or purging has been previously removed; then perhaps the ingestion of Magnesia, or an Alkaline Salt, as proposed by Mr. Marshall, might be admissible, but it should be quickly followed up by fresh emetics and purgatives.
228. London Medical Repository, August, 1817.
229. The truth of this statement has been very satisfactorily established by the experiments of Orfila (Toxicologie générale considerée sous les Rapports de la Physiologie, de la Pathologie, et de la Medicine légale) as well as by several that have been performed in this country.
Tortosa (Istituzioni di Med. For.) has remarked that Opium may act mortally without losing much of its weight in the stomach—I should question the truth of this assertion.
230. Vegetable acids are in Nature rarely the vehicles of poisons, the most deleterious plants being inert in those parts that are impregnated with acid; the pulp of the fruit of the Strychnus, amongst many others, offers an illustration of this fact. Virey.
231. Notwithstanding this fact, we find Venesection recommended in works on Toxicology, as a safe precaution to be used against the inflammatory action produced by arsenic.
The application of a ligature above an abraded surface to which a poison has been applied, prevents its effects upon the constitution, not so much by obliterating the capacity of the vessels, as by inducing a local plethora, and so suspending the process of absorption.
232. Escharotic from ἐσχαρόω, crustam induco, to scab over, to burn into a crust.
233. Or in a still more striking manner, by holding over the surface of the sore a piece of white paper moistened by the mixed solutions of Nitrate of Silver and Arsenious Acid, when the disengaged Ammonia will by the operation of double affinity enable the Arsenious Acid to decompose the salt of Silver, and to display the presence of the Arseniate of that metal by its characteristic yellow indication. I am not acquainted with any test for Ammonia so summary and satisfactory as this. See Arsenicum in Vol. 2 of this work.
234. There are four species of worms generated in the human intestines, viz. The Tænia, or tape-worm—Tricocephalus, or Trichuris—Ascaris Vermicularis, or Ascarides—and Lumbricoides.
235. It is a very curious fact that vegetable bitter should be so essential to the wellbeing of the higher order of animals, as explained at page 79, and yet prove so generally destructive to insects. Flies are almost immediately destroyed by an Infusion of Quassia, and Nature has protected the ear from the invasion of insects by providing an intensely bitter secretion.
236. The reader is also referred to an account of Majendie’s experiments as related at page 86 of this volume.
237. Fish, especially those of the cetaceous tribe, constantly decompose water, and live upon its hydrogen.
238. Rumford’s Essays, Vol. 1. p. 194–202.
239. I selected it as the exclusive subject of my Lectures before the Royal College of Physicians, during the year 1820.
240. It was wisely said by Lord Bacon, “that Man should observe all the workmanship, and the particular workings of Nature, and meditate which of those may be transferred to the Arts.” Advancement of Learning, Book v. 148. For a further illustration of these views, the partiality of an author may perhaps be excused if he refer the reader to his paper “On the Recent Sandstone,” published in the first volume of the Royal Geological Society of Cornwall.
241. The practitioner must receive the term similar, conventionally, as expressed at page 71. Many of those substances which we are at present bound to consider similar, will no doubt, require to be transplanted into other classes as the progress of physiological knowledge shall elucidate their modes of action. In this attempt to teach the Art of Medicinal Combination, I have endeavoured to reduce the propositions it comprehends to the greatest degree of generality of which they are, at present, susceptible.
242. Numerous isolated statements of the same tendency may be adduced, but these cannot invalidate the claim of Dr. Fordyce, as the first person who generalized the fact, and applied it with success to practice. Diemerbroeck, in his notes upon the Theriaca Andromachi, observes that the composition is a more efficacious medicine from the concurrent powers of so many ingredients, alike in virtue: and Quincy, in his Lectures on Pharmacy, which were published by Dr. Shaw in 1723, says “those fetid gums which are generally prescribed in Hysteria, as Ammoniacum, Galbanum, &c. may be conjoined with advantage, because from a concurrence of properties, they all conspire to the same end.”
243. Such was the nature of the “Mustacea” of the Romans, which were a species of cake, used at weddings, and consisted of meal, aniseed, cummin, and several other aromatics; their object was to remove or prevent the indigestion which might be occasioned by eating too copiously at the marriage entertainment. It must be acknowledged that this compound was better adapted for such a purpose than the modern Bride-cake, to which it gave origin. Cato (de R. R. c. 121) has given us a receipt for the Roman bride-cake.
244. Dr. Majendie goes so far even as to assert, that by varying the different preparations of the same Narcotic, we shall be better able to keep up its action on the animal œconomy, without an increase of its dose. He adds, “Some English writers have denied the truth of this observation: but they have not given any reasons for their scepticism.—Why should it not be true?”
245. It would even appear probable that in some cases mercurial influence has, after its subsidence, been renewed by doses of Opium: a remarkable instance of this kind is related in Hufeland’s Journal (vol. ix.) in which an old woman is said to have fallen into a considerable salivation after every dose of Opium; she had previously applied to the physician for an extensive ulceration over her body, and had taken a considerable quantity of mercury; but the effects had subsided, until renewed by the opium.
246. It has been observed under the history of Emetics (p. 84), that in cases of profound intoxication, or in those of violent wounds and contusions of the head, vomiting will not take place, however forcibly the stomach may be goaded by an emetic, whereas if the brain be only partially influenced, as by incipient intoxication, or by a less violent blow on the head, its irritability is increased instead of being paralysed, and that vomiting under such circumstances is excited by the slightest causes; just so is it with regard to Narcotics, a powerful dose so paralyses the nervous system, that the stomach cannot be made to reject its contents, as every one must have observed in cases of narcotic poisoning, while smaller doses, like lesser injuries of the head, dispose the stomach to sickness.
247. Sir Gilbert Blane has advanced an ingenious hypothesis to explain the cause of the fœtid breath of persons under the influence of mercury; which might perhaps also shew why certain remedies are rendered more efficient by combination with mercury. One of the active effects of mercury, says Sir Gilbert, is to alter the natural sensibility of the Lacteals, so that when under its influence, they absorb indiscriminately that which is excrementitious and nutritive; hence the smell of the breath, since the fœtid particles are carried into the circulation, and thrown off in the halitus of the lungs, or by the salivary glands, in consequence of the mouth of the lacteals losing that selecting tact, whereby in their sound state they reject whatever is offered to them, except the chyle. Now if mercury acts as the “Soporata Offa” to the lacteals, it is evident that its combination with active matter may, on some occasions, facilitate the absorption of the latter.
248. In some cases, however, the energy of an active bitter would seem to be diminished by an alkali; and it may therefore be more prudent to administer such substances at different periods. I apprehend that the powers of Squill are thus invalidated by a fixed alkali.
249. The Arabian and Greek physicians scarcely noticed the leaves, but always employed the pods of Senna; a fact which will explain the operation of this plant, as observed by them.
250. Mac Culloch on Wine. Edit. 2. p. 42.
251. If the facts stated in this section be true, we are bound to recognise two orders of medicinal elements,—the one comprehending those that possess an inherent and independent activity,—the other, those that are in themselves inert, but which are capable of imparting impulse and increased energy to the former when combined with them. As this is a new view of the subject of vegetable combinations, no apology is necessary for the introduction of new terms for its explanation; I therefore propose to designate the former of these Substantive, and the latter, Adjective constituents. When the structure of vegetable remedies shall have been thoroughly examined upon this principle of combination, much medicinal obscurity will be removed, and probably some pharmaceutical improvements of value suggested; at all events it will teach a lesson of prudent caution to the pharmaceutic chemist; it will shew the danger of his removing this or that element from a vegetable compound, merely because he finds, upon its separation, that it is inert. I dwell the more upon this point, because I feel that there never was a period in the history of medicine, at which such a caution was more necessary; for while the poly-pharmacy of our ancestors has driven the physician of the present day into a simplicity of prescription that on many occasions abridges his powers and resources, the progress of chemical knowledge has diffused through the class of manufacturing chemists a bold spirit of adventure and empiricism,—a mischievous propensity to torture our best remedies, in order to concentrate or extract the parts which they consider to constitute their essential ingredients.
A Memoir has lately been presented to the Philomatic Society of Paris, by M. Robiquet, on the subject of Aroma, which affords some important analogies in proof of the law of combination, which I am now endeavouring to elucidate. From the experiments of this laborious chemist it would appear, that odours are not as Fourcroy supposed, the effect of the simple solution of certain bodies in air, but that for their developement, some third body (coinciding in its office with my Adjective constituent) possessing in itself none of the characteristic odour, is absolutely necessary as an intermede, varying in its nature according to that of each odorous body, in the same way that the mordant requires to be varied by the dyer, according to the nature of the colouring matter which it is intended to fix on the cloth;—thus Ambergris has in itself very little odour, but the addition of Musk developes a very strong and decided one; this also happens in a less degree with Lavender, and the perfumers therefore add a small quantity of musk to the distilled water of this plant. In other cases, Ammonia lends, as it were, its volatility to bodies, the odour of which without such an auxiliary, would be scarcely sensible; this is exemplified by the practice of perfumers exposing their musk and other substances to the atmosphere of privies when they lose their power: (Paul Amman: Manduct: ad Mat: Med:) so again in order to give pungency to snuff it is made to suffer the commencement of fermentation, in which case ammonia is generated; and it is a curious fact that the odour of the best snuff may be destroyed by mixing with it a little tartaric acid, by which its ammoniacal salt is neutralized. In some instances the adjective ingredient seems to be Sulphur, as in the essential oils of some cruciform plants, and particularly in that of mustard seed, for M. Robiquet found that this oil lost its odour by being kept in contact with a metallic surface, and that an inodorous oil remained, while the metal became a sulphuret: perhaps, adds M. Robiquet, it may be sometimes necessary for the full and exquisite developement of odour in these bodies to add another vehicle, thus the addition of a little Acetic acid heightens the odour of Mustard.
Iron has little, or no odour; but when volatilized with hydrogen, its odour is very powerful. The smell of copper and brass must depend upon some circumstance not well understood.
252. Astruc, and other practitioners of the same school, always premised a mercurial course with venesection: it is probable that many of the anomalies observed in the modern application of this remedy may have arisen from an inattention to the diet of those who are under mercurial influence. Mercury is in itself a most powerful stimulant, and ought therefore to be accompanied with depletion and low diet; besides which, the experiments of Majendie have shewn how greatly such a state of the system will expedite the effects of the mercurial remedy.
253. Dr. Eberle, of Philadelphia, in a work lately published, has quoted the above passage, and remarks, that he has long been acquainted with the fact which it announces; although he proposes to account for it by a different train of reasoning; he considers that Nauseants encourage mercurial ptyalism, by favouring an afflux to the salivary glands. The learned author must allow me to congratulate him upon this fortunate discovery; unless his patients be blessed with as much apathy as was ever assumed by the Gilbertine order of Benedictines, he need never in future despair of influencing them by mercury. He has only to condemn the refractory to meagre fare, and then to tantalize them, as poor Sancho was, in his government, with the sight, or rather smell, of a savoury dish, and he will without doubt secure his object,—but, to be serious, if Dr. Eberle’s views be correct, how will he explain the modus operandi of fear, as related in the text? for the tendency of fear is to diminish the salivary secretion, as will be hereafter mentioned.
254. Fear, contrary to joy, decreases, for a time, the action of the extremities of the arterial system, as is seen by the sudden paleness which succeeds, and the shrinking or contraction of the vessels of the skin. M. de Haen relates the case of a painter who suffered convulsions, which were succeeded by a return of his colic. In this case the poison which had been, for a long time, admitted into his constitution in consequence of his daily employment, was, by the passion of anger, immediately brought into action. It was formerly observed by Citois, that the inhabitants of the province of Poitou, who had suffered anxiety of mind on account of any misfortune to themselves or family, were particularly susceptible of the disease.
255. How admirably do the results of Majendie’s experiments coincide with this reasoning; see page 84; and yet Dr. Eberle, in the work quoted below, appears unwilling to admit such a theory.
256. A treatise of the Materia Medica, and Therapeutics, by J. Eberle, M.D. In two volumes. Philadelphia, 1822.
257. In the same manner is the salivary secretion immediately influenced by the operation of the mind; the sight of a delicious repast to a hungry man is not more effectual in exciting it, than is the operation of fear and anxiety in repressing and suspending it. Whence we are led to believe, that the Hindoo Ordeal by Rice may have occasionally assisted in the ends of Justice. This ordeal was conducted in the following manner. The persons suspected of any crime being assembled in a ring, a certain portion of dried rice was given to each, which they were directed to chew for some minutes, and then to turn it out of their mouths upon the leaves or bark of a tree. Those who were capable of returning it in a pulpy form were at once acquitted, while those from whose mouths it came out dry, were pronounced guilty. See Medical Jurisprudence, Introduct. Vol. 1. p. viii.
258. The capacity of our digestive organs sufficiently testifies that nature never intended them for the reception of highly concentrated food, while this idea is farther strengthened by perceiving how sparingly she produces concentrated aliment; the saccharine matter of esculent fruits is generally blended with acidulous and mucilaginous ingredients; and the oleaginous principle of seeds, kernels, and other similar substances, is combined with farinaceous matter: the capacity observable in the organs of graminivorous animals evidently shews that they were also designed for a large bulk of food, and not for provender in which the nutritive matter is concentrated; the gramineous and leguminous vegetables do not present their nutritive matter in a separate state, nor is the animal furnished with an apparatus by which he can separate the chaff and straw from the grain,—the obvious inference is, that he was intended to feed indiscriminately on both.
Some years ago I constructed a Logometric scale of Equivalents, analogous in principle to that which I have now introduced under the title of the “Medicinal Dynameter,” to shew the relative nutritive strength of different vegetables, and to work problems connected with them; I soon found, however, that unless bulk was taken into calculation, it was incapable of furnishing even an approximation to truth.
259. Med. Repos. Nov. 1822.
260. A Practical Inquiry into Disordered Respiration, p. 243.
261. D. Young’s Medical Literature, Edit. 2. p. 570.
262. The vegetable kingdom presents us with many natural compounds of this kind; several of which might be pressed into the service of medicine with much advantage. With respect to the number and variety of such substances, it must be confessed that our Pharmacopœia contains but a meagre bill of fare.
263. The same reasoning will explain why English hops, that contain more Gallic Acid and Tannin than those imported from the Continent, are found to be superior as preservatives of beer.
264. Therapeutics, vol. 2. p. 470.
265. This subject has been ably illustrated by Mr. R. Phillips, in his translation of the London Pharmacopœia, by a series of vary striking and instructive diagrams.
266. See my work on Medical Chemistry: Sect. Precipitation.
267. An ingenious application of this law has been made for the purpose of purifying Epsom Salts. See Magnesiæ Sulphas; and also my work on Medical Chemistry, Art: Solution.
268. Amœnitates Academ; T. 7. p. 307.
269. See also a paper in the Medical Transactions, vol. 2. entitled, “Several extraordinary instances of the cure of Dropsy, by George Baker, M. D. Read September 9, 1771.”
270. The most subtle of all poisons,—the matter of febrile contagion,—is certainly modified in activity by the degree of moisture in the atmosphere influencing its solubility; the Plague is said to be most common in Egypt after the inundation of the Nile, a period at which the atmosphere is necessarily saturated with water; according to the account of Sir Robert Wilson, the English and Turkish armies that marched to Cairo escaped contagion, while the troops that remained stationary on the moist shore of Aboukir, were very severely visited. On the other hand, the Harmattan, a wind experienced on the western coast of Africa, between the Equator and fifteen degrees North Latitude, blowing from north-east towards the Atlantic, and which, in consequence of its passage over a very extensive space of arid land, is necessarily characterized by excessive dryness, puts an end to all Epidemics, as the Small Pox; and infection at such a time does not appear to be easily communicable even by art. Philosophical Transactions, vol. 21.
The difficulty of communicating infection to animals during a dry state of the air, as remarked on the Western Coasts of Africa, during the blowing of the Harmattan, agrees with some observations on Plague by the French physicians, as this complaint first made its appearance in the French army during a moist state of the air in Syria, when it lay under the walls of Jaffa in February, 1800.
It is a well known fact that volatile bodies are sooner converted into a gaseous state by the presence of water in the atmosphere; this is strikingly exemplified by the greater rapidity with which Limestone is burnt and reduced to quick-lime in moist weather, and by the assistance which is rendered in a dry season, by placing a pan of water in the ash-pit; so again the perfume of flowers is most sensible when the air is humid, as during the fall of the evening dew, or in the morning when the dew evaporates, and is dissipated by the rays of the rising sun; for the same reason the stench of putrid ditches and common sewers, is conveyed to the organs of smell much more speedily in summer previous to rain, when the air is charged with moisture.
271. They are previously calcined, but not burnt to lime, to an extent only that may destroy their tenacity, and render them fit for levigation.
272. A similar custom is common to the Indians of the whole of Asia, and of America; for the practice of the South American Indians, see Humboldt’s Personal Narrative. In India, Betel, variously compounded, is employed for the purpose above stated. The mixture more commonly used in Ceylon consists of quick-lime, Arecanut, and Tobacco, wrapped in Betel leaf. On ordinary occasions it is only masticated; but to repress the painful calls of hunger, the juice is swallowed.
273. Vol. viii. p. 33.
274. Dr. MacCulloch, in illustration of this subject, states, that ink, paste, and seeds, are among the common articles which suffer from such a cause, and to which this remedy is easily applicable. With respect to articles of food, such as bread, cold meats, or dried fish, it is less easy to apply the remedy, on account of the taste; cloves, however, and other spices whose flavours are grateful, may sometimes be used for this end. It is notorious that gingerbread, and bread containing caraway seeds, are far less liable to mouldiness than plain bread. The effect of cloves in preventing the mouldiness of ink is generally known; and the same result may be obtained by oil of lavender in a very minute quantity, or by any other of the perfumed oils. Russian leather, which is perfumed with the tar of the Birch tree, is not subject to mouldiness, as must be well known to all who possess books thus bound; they even prevent it from taking place in books which are bound in calf, and near which they may happen to lie. Paste is another perishable article, and although Alum which is used by the book-binder will certainly preserve it longer than it would remain useful without it, still it is not very effectual. Rosin, sometimes used by the shoemaker, answers the purpose better, and appears to act entirely on this principle; it is however far less effectual than even oil of turpentine; Lavender, and the other strong perfumes, as Peppermint, Anise, and Bergamot, are perfectly effectual, even in a very small quantity, and paste may be thus preserved for any length of time.
275. Medical Logic, Edit. 2. p. 192, note.
276. It appears from what has been stated under Section I. B. with respect to Diuretics, that some medicines not only assist, but actually DIRECT the operation of the substances with which they may be associated, and that many remedies act in unison with those they are joined with; thus Nitre in conjunction with Squill is diuretic; in conjunction with Guaiacum, diaphoretic; for these reasons I hesitated whether I ought not to have added a fifth constituent, and restored the “Dirigens” of ancient authors; enough, however, has been said to enable the practitioner to appreciate the importance of such a law of medicinal combination.
277. Dr. Percival in his Essays, ingenuously exemplifies this error by stating a case which occurred in his own practice. “I ordered,” says he, “a combination of Camphor and Balsam of Copaiba in the form of pills, but the apothecary informed me that he was unable to form them into a mass, since they liquefied like treacle.” I may here observe that the addition of a small portion of the coagulated yolk of an egg, would have rendered the mixture practicable.
278. This would occur, if in making the Pilulæ Ferri Compositæ, we were to substitute the Liquor Potassæ for the Sodæ Sub-carbonas.