In cases where there is ecchymosis of the eyes, or a bruise from the effects of a blow, salt is applied, with an equal quantity of myrrh and honey, or with hyssop in warm water, the eyes being also fomented with salsugo. For this last-mentioned purpose, the Spanish salt is preferred; and when wanted for the treatment of cataract, it is ground upon small whetstones, with milk. For bruises it is particularly useful, wrapped in a linen pledget and renewed from time to time, being first dipped in boiling water. For the cure of running ulcers of the mouth, it is applied with lint; gum-boils are also rubbed with it; and, broken to pieces and powdered fine, it removes granulations on the tongue. The teeth, it is said, will never become carious or corroded, if a person every morning puts some salt beneath his tongue, fasting, and leaves it there till it has melted. Salt effects the cure also of leprosy, boils, lichens, and itch-scabs; for all which purposes it is applied with raisins—the stones being first removed—beef-suet, origanum, and leaven, or else bread. In such cases it is the salt from Thebaïs that is mostly used; the same salt being considered preferable for the treatment of prurigo, and being highly esteemed for affections of the uvula and tonsillary glands, in combination with honey.
Every kind of salt is useful for the cure of quinzy; but, in addition to this, it is necessary to make external applications simultaneously with oil, vinegar, and tar. Mixed with wine, it is a gentle aperient to the bowels, and, taken in a similar manner, it acts as an expellent of all kinds of intestinal worms. Placed beneath the tongue, it enables convalescents to support the heat[3178] of the bath. Burnt more than once upon a plate at a white heat, and then enclosed in a bag, it alleviates pains in the sinews, about the shoulders and kidneys more particularly. Taken internally, and similarly burnt at a white heat and applied in bags, it is curative of colic, griping pains in the bowels, and sciatica. Beaten up in wine and honey, with meal, it is a remedy for gout; a malady for the especial behoof of which the observation should be borne in mind, that there is nothing better for all parts of the body than sun and salt:[3179] hence[3180] it is that we see the bodies of fishermen as hard as horn—gout, however, is the principal disease for the benefit of which this maxim should be remembered.
Salt is useful for the removal of corns upon the feet, and of chilblains: for the cure of burns also, it is applied with oil, or else chewed. It acts as a check also upon blisters, and, in cases of erysipelas and serpiginous ulcers, it is applied topically with vinegar or with hyssop. For the cure of carcinoma it is employed in combination with Taminian[3181] grapes; and for phagedænic ulcers it is used parched with barley-meal, a linen pledget steeped in wine being laid upon it. In cases of jaundice, it is employed as a friction before the fire, with oil and vinegar, till the patient is made to perspire, for the purpose of preventing the itching sensations attendant upon that disease. When persons are exhausted with fatigue, it is usual to rub them with salt and oil. Many have treated dropsy with salt, have used external applications of salt and oil for the burning heats of fever, and have cured chronic coughs by laying salt upon the patient’s tongue. Salt has been used, also, as an injection for sciatica, and has been applied to ulcers of a fungous or putrid nature.
To bites inflicted by the crocodile, salt is applied, the sores being tightly bandaged with linen cloths, first dipped[3182] in vinegar. It is taken internally, with hydromel, to neutralize the effects of opium, and is applied topically, with meal and honey, to sprains and fleshy excrescences. In cases of tooth-ache, it is used as a collutory with vinegar, and is very useful, applied externally, with resin. For all these purposes, however, froth of salt[3183] is found to be more agreeable and still more efficacious. Still, however, every kind of salt is good as an ingredient in acopa,[3184] when warming properties are required: the same, too, in the case of detersive applications, when required for plumping out and giving a smooth surface to the skin. Employed topically, salt is curative of itch-scab in sheep and cattle, for which disease it is given them to lick. It is injected, also, with the spittle, into the eyes of beasts of burden. Thus much with reference to salt.
CHAP. 46. (10.)—THE VARIOUS KINDS OF NITRUM, THE METHODS OF PREPARING IT, AND THE REMEDIES DERIVED FROM IT: TWO HUNDRED AND TWENTY-ONE OBSERVATIONS THEREON.
And here we must no longer defer giving an account of nitrum;[3185] which in its properties does not greatly differ from salt, and deserves all the more to be attentively considered, from the evident fact that the medical men who have written upon it were ignorant of its nature; of all which authors Theophrastus is the one that has given the greatest attention to the point. It is found in small quantities in Media, in certain valleys there that are white with heat and drought; the name given to it being “halmyrax.”[3186] In Thracia, too, near Philippi, it is found, but in smaller quantities, and deteriorated with earthy substances, being known there as “agrion.”[3187] As to that prepared from the burnt wood of the quercus,[3188] it never was made to any very great extent, and the manufacture of it has been long since totally abandoned. Nitrous[3189] waters are also found in numerous places, but not sufficiently impregnated to admit of condensation.[3190]
The best and most abundant supply is found at Litæ, in Macedonia, where it is known as “Chalastricum:”[3191] it is white and pure, and closely resembles salt. In the middle of a certain nitrous lake there, a spring of fresh water issues forth. In this lake the nitrum[3192] forms for nine days, about the rising of the Dog-star, and then ceases for the same period, after which it again floats upon the surface, and then again ceases: facts which abundantly prove that it is the peculiar nature of the soil which generates the nitrum, it being very evident that, when the formation is there interrupted, neither the heat of the sun nor the fall of rain is productive of the slightest effect. It is also a truly marvellous fact, that though the spring of fresh water is always uninterruptedly flowing, the waters of the lake never increase or overflow. If it happens to rain on the days during which the nitrum is forming, the result is, that it is rendered additionally salt thereby: the prevalence of north-east winds, too, still more deteriorates its quality, as they have a tendency to stir up the mud at the bottom. Such is the formation of native nitrum.
In Egypt, again, it is made artificially, and in much greater abundance, but of inferior quality, being tawny and full of stones. It is prepared in pretty nearly the same manner[3193] as salt, except that in the salt-pans it is sea-water that is introduced, whereas in the nitre-beds it is the water of the river Nilus; a water which, upon the subsidence of the river, is impregnated with nitrum for forty days together, and not, as in Macedonia, at intermittent periods only. On occasions when there has been a fall of rain, a smaller proportion of river-water is employed. As soon, too, as any quantity of nitrum has formed, it is immediately removed, in order that it may not melt in the beds. This substance, also, contains a certain proportion of oil,[3194] which is very useful for the cure of scab in animals. Piled up in large heaps, it keeps for a very considerable time. It is a marvellous fact, that, in Lake Ascanius[3195] and in certain springs in the vicinity of Chalcis, the water is fresh and potable on the surface, and nitrous below. The lightest part of nitrum is always considered the best, and hence it is that the froth of it is so much preferred. Still, however, when in an impure state, it is very useful for some purposes, colouring purple[3196] cloth, for instance, and, indeed, all kinds of dyeing. It is employed, also, very extensively in the manufacture of glass, as we shall more fully mention on the appropriate occasion.[3197]
The only nitre-works in Egypt were formerly those in the vicinity of Naucratis and Memphis; those near Memphis being inferior to the others, the piles of nitrum there prepared being as hard as stone, and many of the heaps having become changed into rocks. When in this state, vessels are made of it, and very frequently they melt it with sulphur[3198] on a charcoal fire.[3199] When substances[3200] are wanted to keep, they employ this last kind of nitrum. In Egypt there are also nitre-beds, the produce of which is red, owing to the colour of the earth in the same locality. Froth of nitrum,[3201] a substance held in very high esteem, could only be made, according to the ancients, when dews had fallen; the pits being at the moment saturated with nitrum, but not having arrived at the point of yielding it. On the other hand, again, when the pits were in full activity, no froth would form, it was said, even though dews should fall. Others, again, have attributed the formation of this last substance to the fermentation of the heaps of nitrum. In a succeeding age, the medical men, speaking of it under the name of “aphronitrum,”[3202] have stated that it was collected in Asia, where it was to be found oozing from the soft sides of certain mines—the name given to which was “colyces”[3203]—and that it was then dried in the sun. The very best is thought to be that which comes from Lydia; the test of its genuineness being its extreme lightness, its friability, and its colour, which should be almost a full purple. This last is imported in tablets, while that of Egypt comes enclosed in vessels pitched within, to prevent its melting,[3204] the vessels being previously prepared by being thoroughly dried in the sun.[3205]