Kitabı oku: «The History of Salt», sayfa 2
Our speculations on this point are, however, comparatively vain, for we cannot possibly determine who first discovered it, or who first utilised it as a condiment to food: all we really know is that it has become universal, and that from time immemorial; but whether the Egyptians, Chinese, or Hindoos first made use of it, will be one of those dark secrets the solution of which may interest the curious and ingenious, and test the patience and erudition of the profound. Such an investigation might probably be considered by some as unprofitable, even if it were attended with success. To such I do not think it will be unjust or irrelevant to observe that many scientific discussions which from time to time have occupied the learned world have been, as far as the results are concerned, not of much moment to humanity at large. For instance, of what practical utility is the modern theory of evolution, upon which so much erudition of a minute kind, and thought, is expended, except as indicative of the ingenuity of the author? Is science at all advanced when we are gravely told that the human organism springs from protoplasm, and that plastidules consist of carbon, hydrogen, oxygen, and nitrogen, and that they possess souls? It is true that these abstruse inquiries have been productive of inciting a greater desire for studying the workings of nature, and a great deal of which previous generations were profoundly ignorant has been ingeniously disclosed, and accurately elucidated, for one is bound to admit that, though in many instances their researches have failed in their ultimate results, they have been the indirect cause of giving a remarkable impetus to scientific investigation. Many recondite subjects have thus been exhaustively analysed, unintentionally, owing to the anxiety and eagerness of the authors to arrive at the goal of their wishes; for while they are seeking for that which probably will never be found, they discover others which, to all intents and purposes, very likely would never have been conceived of. Perhaps these remarks may be considered unjust and hypercritical as regards their researches into the mysteries of life, and do not appear to give sufficient importance to those philosophical deductions and enunciations, which the authors no doubt demand as an imperative right; for scientific physicists are apt to be tyrannical, and are not over-endued with the virtue of practicality, and naturally do not like their opinions and metaphysical reveries relegated to that region which Milton humorously baptized the “Paradise of Fools,” but prefer their speculations to be regarded as irrefragable facts. As this is, however, the age for far-fetched theories, I think we may be allowed with perfect fairness to discuss a subject which has partially escaped the eyes of the inquisitive; and if it is not treated so elegantly as the learned theses of the leaders of science and philosophy of to-day, I cannot help thinking that we may probably gain considerably more by studying a subject which is practically of interest to all, than attempting to penetrate into the invisible and undefinable mechanism of biology.
Notwithstanding the proofs (vague though they be), which I have already mentioned to show that we are indebted to the Egyptians for the discovery of this most valuable substance, I nevertheless do so with diffidence, because they are of a hypothetical tendency, and consequently refutable.17 We may endeavour to trace the custom of using salt as a condiment to several nations, or even to one particular nation, with as much earnestness as the modern speculatists attempt to account for unaccountable phenomena appertaining to the material and spiritual worlds; but, as far as the real evidence goes, we are as unsuccessful, and our inquiries almost as unsatisfactory, as theirs have been hitherto.
There is great probability, however, that the Egyptians first made known to other nations, directly and indirectly, the utility of salt, and that through their sole agency it was introduced into Europe through the media of commerce and other channels of communication, and no doubt, as I have previously stated, in deference to their superior wisdom. We learn from those scholars who are giving their attention to Egyptian remains, that Greece was indebted to Egypt for all her science, architecture, literature, art, and mythology; and, indeed, her domestic life was derived from that venerable country. “From Egypt, it now appears, were derived the prototypes of the Greek architectural orders, and even their monuments and conventional designs; thence came the models of the Greek and Etruscan vases; thence came many of the ante-Homeric legends … thence came the first ritual for the dead, litanies to the sun, and painted, or illuminated, missals; thence came the dogma of a queen of heaven!”18
In confirmation of this we are told that Moses, as I have before remarked, was skilled in Egyptian wisdom: this is most emphatic, and we cannot but conclude that that wisdom was in a high state of perfection; and their works, which are still the surprise and admiration of travellers, testify to the truth of Holy Writ. Do not their monuments, which have set time at defiance, prove that they were a people highly gifted? Their ruins are more sublime than any other architectural remains which are extant, excelling, both in magnificence and magnitude, the classic temples of Greece, and the elegant buildings which once graced the banks of the golden Tiber. In reference to this I may quote Dr. Lepsius, who states that “all the principal cities of Egypt were adorned with temples and palaces… These temples were filled with the statues of gods and kings, generally colossal, and hewn from costly stones.”
Possibly, owing to the fact that salt is valued almost universally, and is a substance which has been demonstrated by experience to be necessary to humanity, it may have been, for all we can say, as well known to the Antediluvians as it is to us; and if so, then we are indebted to Noah. But these are but surmises; we really possess no authentic record, except that which we find in Holy Writ: and, with my reader’s leave, we will now proceed to examine those passages of Scripture in which salt is mentioned.
We find that whenever salt is named, it is done so in language of a character stamping it as a most important essential; and especially do we notice this in the directions for the religious services of the Israelites. They were commanded in the most explicit language that in all their offerings they should “offer salt.”19 There is also another point which we must not omit, and that is, whenever salt is referred to in the Inspired Volume, it is invariably in connection with some important transaction: for example, when Elisha sweetened the waters of the fountain of Jericho, he cast salt into them; this act of the prophet illustrates, figuratively, the purifying properties of salt, for he said, “I have healed these waters.”20 When Abimelech captured Shechem, he strewed salt over the ruins;21 and when Abijah harangued Jeroboam from the Mount Zemaraim, he speaks of a “covenant of salt.”22 We read farther on of this “covenant of salt” in the Book of Numbers.23 In fact, in the Old Testament, as well as in the New, considerable stress is laid on this evidently important substance, which shows that nothing was considered as thoroughly accomplished if salt, in some way or other, was not intimately connected with it.
It was also a custom amongst the Hebrews, which was never departed from, to rub new-born infants with salt:24 this practice was in every respect healthy and cleanly, and if we Christians were wise we should, from a hygienic point of view, strictly follow a custom which is so conducive to health; for salt hardens the skin of newly-born children and renders it more firm, and prevents (unless there is an hereditary taint) any irritation or local eruption of the skin.
The first mention of salt as a condiment is to be found in Job;25 and as this beautiful book, which delineates the vicissitudes to which life is subjected, is supposed to have been written by Moses when he was dwelling amongst the Midianites, there is no doubt but that it was in general use not only in Egypt, but also amongst the surrounding nations. The answer to the question propounded by the persecuted man of Uz is the same now as it was three thousand years ago – there is nothing savoury without salt, and to a certainty there is no real permanent health without salt.
The Jews, like all Asiatic races, were much afflicted with various forms of leprosy, and as salt is an indirect antidote to cutaneous eruptions, they used it not so much as a condiment, but as a shield to ward off and protect them from those repulsive diseases which rendered those who were attacked obnoxious to their fellow-countrymen, by whom they were treated as outcasts till they had recovered from their loathsome maladies. To this day we find that by far the greater number who suffer from cutaneous diseases hardly ever eat salt with their food; this is an unquestionable fact, and truly significant of its inestimable virtue as an anti-morbific agent.
The Great Master says (and who will dispute such an unanswerable verity?) “salt is good;” and then He adds, “but if the salt has lost its saltness, wherewith will ye season it?”26 Addressing His disciples, He says: “Ye are the salt of the earth,” and also, “Have salt in yourselves.”27 These sayings prove in the most unmistakable language that salt is highly necessary. Our Saviour applies it in a religious sense, it is true, but He was too much of a philosopher, too great a logician, to use a metaphor of which the application could be shaken and disproved in the abstract, if the image or figure were fundamentally incorrect or inconsistent with the lesson which it was intended to convey; besides, He never would have declared it “good” had it been in the slightest degree provocative of anything deleterious to the human race, neither would He have made use of a figurative mode of speech if He could not have based it on a physical fact.
We are thus told in three simple words the value of salt, and none save the shallow, or the sophist, would attempt to prove the contrary. All must acknowledge the fact that salt is equally pleasant to the gourmand and the temperate; and that animal and vegetable food is not palatable without it. As it is pronounced to be “good” by the highest authority, we must regard it as one of Heaven’s best gifts to man. It would be a comparatively small matter were it but a condiment rendering food more pleasant to the taste; but when we know that it is indirectly a preserver of health, and that it also contravenes the attacks of disease, its value will, I hope, be considerably increased.
I shall be more than satisfied if I am able to persuade those unwise people who make it a rule never to use salt, to resort to it at once without hesitation; for if they wish to be in a fair state of health, to have clear wholesome skins and fresh complexions, to be free from intestinal parasites and cutaneous diseases, to have their digestive organs perform their functions compatible with health and personal comfort, they must have, practically speaking, salt in themselves.
We have thus, from very scanty records concerning salt, essayed to clear up, though very inconclusively, and I fear unsatisfactorily, certain points which have been unnoticed, by reason, I think, of the dense obtenebration with which the subject is surrounded; for it has hitherto baffled the researches of the geologist to discover its pristine source, and neither do we know who first used it as a condiment. The chemist can experimentalise with this inorganic substance to detect the presence of other bodies, and he knows its worth in the laboratory; but as for its origin, he is as much in the dark as the geologist.
CHAPTER III
SALT AS A CHEMICAL, THERAPEUTICAL, AND TOXICOLOGICAL AGENT
As a chemical agent, and from the manufacturing uses to which it is now put, salt is a most invaluable article from a scientific as well as from a commercial point of view. I will therefore draw the attention of my reader to its chemical properties; I will then allude to a few drugs which are partially derived from salt or the chloride of sodium; and will cursorily notice one great staple of commerce which owes the rapidity of manufacture to its sole agency, including some remarks on it as a poison.
Chlorine gas, which is obtained from the chloride of sodium, was discovered by Scheele in 1777, who named it dephlogisticated muriatic acid. Berthollet in 1785 termed it oxygenated muriatic acid. Sir Humphry Davy called it chlorine (from χλωρὸς, green) on account of its colour, and it has kept this name ever since. We thus see that salt is of great use to the chemist, for he not only obtains chlorine gas from it, but also hydrochloric acid, a most useful and efficacious drug in the treatment of some hepatic diseases. Chlorine also enters into combination with other chemical substances known as chlorides and chlorates, sub-chlorides and per-chlorides; for instance, we have the chloride of ammonium and the chlorate of potash; we also have the sub-chloride of mercury, or calomel, and the perchloride of mercury, or corrosive sublimate, with various others.
According to Pereira, hydrochloric acid was known to Djafar, or Geber, an Arabian chemist who flourished in the eighth century, and whom Roger Bacon calls magister magistrorum. Everyone is acquainted with the chloride of lime, a substance so generally used for household and disinfecting purposes, that I need only mention it; besides this, there are other salts with which chlorine enters into combination.
Formerly, to bleach cotton it was required to expose the material to the action of the sun and air, rendering the process long and tedious, as it took on the average quite six or eight months, and likewise a large surface of land was necessary for the operation.
Now, owing to chlorine gas, the process is completed in a few hours, and a comparatively small building is quite sufficient for the purpose; the fibre is beautifully and permanently whitened, and the manufacturer experiences the pleasing satisfaction of a more rapid remuneration.
Where would be our delicately white textile fibres were it not for the abundant and inexhaustible supply of salt? How should we be enabled to cause vegetable colours to vanish as if touched by the hand of a magician were it not for the bleaching properties of chlorine? And how should we be able to procure this green-coloured gas which produces these changes were it not for the chloride of sodium?
As a therapeutical agent chlorine possesses some characteristics peculiar to itself: it is used as a lotion for cancerous growths and foul ulcers, also for some cutaneous eruptions. It is likewise used as a vapour-bath; it has also been used in the treatment of chronic bronchitis and phthisis, and as a gargle in certain morbid conditions of the mouth. When chlorine is absorbed by the system it is supposed to possess some antiseptic and alterative action, acting specifically on the liver.
There is one more fact of a chemical nature in reference to chlorine which it would be unwise to throw aside, as it possesses some degree of interest. When the chemist wishes to decompose water, or in other words to liberate hydrogen from oxygen, he has no better agent to effect the purpose than this greenish-coloured gas, because it has such a strong affinity for hydrogen, which is one of the most characteristic properties of chlorine. Mix them together, and they combine with explosive violence if they are exposed to the beams of the sun. By this process we obtain hydrochloric acid gas, while the oxygen is liberated.
Chlorine only becomes active when it is associated with moisture; when dry it is quite inert as regards its bleaching powers, for “when moist it gradually decomposes the water, combining with its hydrogen, and disengaging its oxygen; and it is this oxygen, at the moment of its liberation, which is the really active agent in bleaching.”28
Salt, like other inorganic compounds, has been known to act as a poison when taken in a large quantity, and Dr. Alfred Taylor, the eminent toxicologist, mentions a case in which a table-spoonful was taken by mistake for sugar; there was no vomiting or purging, but great pain in the region of the stomach, with dryness of the fauces, which lasted several days. Did not the above emanate from so great an authority, one would feel inclined to question it. Could anyone take such a large amount and swallow the same without being immediately aware of his mistake? Surely he would have immediately and spasmodically ejected it by reason of its extremely pungent character, before it had even reached the fauces.
Dr. Taylor says that “in a toxicological view it is not easy to distinguish the effects of common salt in these cases from the poisonous action of salt of sorrel, or binoxalate of potash, which it is well known may be taken with impunity in small quantity;” the symptoms are those of irritant poisoning, causing great pain and intensely inflaming the stomach and intestines, and in those few cases which we have on record the vomiting was excessive.
In France, though not hitherto, as far as I am aware, in Great Britain, several instances have occurred of severe sickness in particular localities, which have been traced to the adulteration of common salt with certain deleterious articles. In an investigation conducted by M. Guibourt some years ago, in consequence of some severe accidents which were presumed to have been produced apparently by salt in Paris and at Meaux, oxide of arsenic was detected; and this discovery was corroborated by MM. Latour and Lefrançois, who ascertained that the proportion of arsenic was sometimes a quarter of a grain per ounce. Another peculiar adulteration which was frequent was with the hydriodate of soda. At a meeting of the Parisian Academy of Medicine, held in December, 1829, an interesting report was read by MM. Boullay and Delens, subsequent to the inquiry by M. Sérullas, into the nature of a sample of salt which occasioned very extensive ravages. In the year 1829 various epidemic illnesses in several parishes were supposed to have originated from salt of bad quality, and in one month no less than 150 people in two parishes were attacked, some with nausea and pain in the stomach, slimy and bloody purging, some with tension of the abdomen, puffiness of the face, inflammation of the eyes, and œdema of the legs; and in some districts of the Marne one-sixth part of the inhabitants were affected in a similar manner. The salt being suspected, as it had an unusual odour somewhat like the effluvia of marsh land, it was analysed by M. Sérullas, and after him by MM. Boullay and Delens; the experiments of all three indicated the presence of one hundredth of its weight of hydriodate of soda, besides a small amount of free iodine. Owing to the discovery of arsenic by other experts in different samples of suspected salt, M. Sérullas repeated the analysis, but was unable to detect the slightest trace of that poison.
“M. Barruel states that he observed the occasional adulteration of salt with some hydriodate accidentally in 1824, while preparing experiments for Professor Orfila’s lectures. He also found it in two samples from different grocers’ shops in Paris. No satisfactory explanation has yet been given of the source of the adulteration with arsenic; but the presence of the hydriodate of soda has been traced to the fraudulent use of impure salt from kelp.”29
It will be as well for us to know what pure salt really consists of, to the composition of which I now draw the reader’s attention:
Composition of the Pure Chloride of Sodium.
MM. St. Claire Deville and Fouqué have shown that common salt can be resolved into its elements by the action of hot steam alone, which Lussa and other chemists had thought impossible.
Prof. Meyer, of Berne, has lately demonstrated by experiments on chlorine gas, that the assumption of its elementary character is an error, and that it is nothing more or less than the oxide of a metal which he calls murium. This discovery opens up an interesting question for physiological chemists to investigate; for if he is correct, chlorine is not an element, but is simply the oxide of a metal.
