Homeopathic Materia Medica by Farrington
There are many of the acids, many more in fact than have been placed on the board. There are not many of them, however, with which we are thoroughly acquainted, and there are but few facts that may be stated with reference to others. The very idea of acid, you will at once understand, implies that they are more or less electro-negative. They all combine very readily with the electro-positive substances, as potassium and sodium. You must rid yourself of the impression that the term "acid" necessarily implies that these substances are sour, for all acids are not sour nor do all acids redden litmus paper. It was formerly supposed that all acids contained oxygen and that oxygen was one of their necessary ingredients. This has been disproved, for certain acids —as hydrofluoric and muriatic acids—contain no oxygen. These acids are derived from the mineral and vegetable kingdoms. Of those derived from the former, we use in medicine Fluoric and Muriatic acids, which are obtained from the halogens ; Nitric acid, a combination of nitrogen and oxygen; Sulphuric acid, Phosphoric acid, Silicea or Silicic acid, which exists as sand in nature and is by no means sour. So, too, the substance which we term Arsenicum is an acid—Arsenious acid.
Then we have derived from organic chemistry Hydrocyanic acid, sometimes called Prussic acid. That, we shall find, exists in a great variety of plants. Then here is Oxalic acid. That you are somewhat familiar with. Many of you who have tasted the "sorrel grass" know how sour the leaves are. It is Oxalic acid which gives them their acidity. It exists also in the rhubarb. Rhubarb, either the medicinal or the edible variety, may or may not be poisonous. When raised on new ground it is very apt to contain an undue amount of Oxalic acid, and thus may make some persons very sick. Malic and Citric acid are derived from the vegetable kingdom. Malic acid is found more particularly in apples and pears and also in raspberries. Citric acid is found chiefly in oranges and lemons. Acetic acid is an organic acid and is the principal ingredient of vinegar. Lactic acid is derived from sour milk.
In the first place we may say a few words about the acids in general and tell what characterizes them as a class. It has been determined by careful experimentation with the acids as a class, that they decrease the acid secretions of the body and increase the alkaline. If, for instance, a quantity of acid, such as Citric acid, is taken into the stomach, it will diminish the secretion of the gastric juice. On the other hand, it will increase the secretion of the saliva. The practical value of this hint is hygienic rather than therapeutic, and yet in that degree it is of great use. For instance, we know how intolerable, at times, thirst is in fevers. Now this thirst may be due, at least in part, to lack of secretion from the salivary glands. The mouth is parched and dry; the tongue cleaves to the roof of the mouth. In such cases as this, acidulated drinks, by acting reflexly, increase the flow of saliva, and will give your patient great relief. For instance, you may give lemonade, providing, of course, it is not antagonistic to your indicated remedy, for there are some medicines which Citric acid will antidote and some which will disagree with it. Again, if you are giving Belladonna, you would not think of using vinegar, as vinegar retards the action of that drug. But when giving Belladonna you may use lemonade, as that aids the action of the remedy. Antimonium crudum will not tolerate acids, but you may use tamarind water. Now if you find the mouth or throat sore in fever, the "edge" must be taken off the acid by the admixture of some mucilaginous substance to the drink. You may use gum Arabic, but that interferes with digestion somewhat. Irish moss, Iceland moss and slippery-elm are too medicinal. They all act powerfully on the lungs and you might induce medicinal symptoms if you employ them. Flaxseed has some medicinal effect, but not sufficient to make its use inappropriate. Another substance which may be used is gelatin, that is, if you know that it is made properly. Some of it is made from the refuse of the tanner; some from fish-bones, and that is quite palatable; but best of all is that made from calves' feet. This last may be used in water to relieve this sharpness.
We find that the acids may be useful in dyspepsia, not as remedies (their therapeutic uses we shall see presently), for we are now speaking of their hygienic applications. You may give them, for instance, in sour stomach. You then administer the acid before eating. Allow the patient to drink lemonade before meals and you will often find that the usual heartburn and sour risings after eating are thus diminished. Pepsin, which is often used as an adjuvant in the treatment of dyspepsia, is perfectly allowable, as it does not interfere with the action of any medicine and is not itself a medicine, and is often aided in its action by some kind of acid, particularly in the digestion of nitrogenous articles of food.
Vinegar has been used as an antidote for intoxication.
There is a property of the Lactic acid which is well worth noticing. This is a very corrosive acid. It will eat into every tissue of the body. In fact, it will dissolve the enamel of the teeth, so that great care must be used in its administration. When prescribed in material doses, it is usually administered through a tube, which prevents it from touching the teeth. Dr. Hering was in the habit of recommending that the teeth be washed occasionally with cream that had become sour by keeping twenty-four hours.
Muriatic and Lactic acids favor digestion. Some persons are greatly relieved by drinking sour milk.
Sulphuric acid must be avoided in any form whatever, because it tends to make the food insoluble by combining with its albuminous constituents. Sulphuric acid is not used in dietetics, except by children in the "sour-balls," which are acidulated almost exclusively with this acid.
Hydrocyanic acid certainly aids digestion. There are some persons who have been cured of dyspepsia by eating peach-kernels, which contain this acid.
There is a distinction between the mineral acids on one side and the organic acids on the other. The mineral acids as a class all produce an irritability of fibre together with weakness and prostration. I am now speaking of their medicinal effects. You will find them to produce an irritable weakness — the pulse is weak and irritable—whereas the vegetable acids produce weakness without irritability. The acids, too, as a class, check haemorrhages. This is a quality that belongs to nearly all of them. We all know that Acetic acid is useful in checking haemorrhage. When I have a patient who is subject to haemorrhage, I am in the habit of instructing the nurse in case haemorrhage sets in before I can be called, to dip a cloth in vinegar and place it over the pubes. In many cases, this will be successful. We all know, too, that Citric acid will produce and cure haemorrhage. A child, after eating too freely of lemons, had haemorrhages from every orifice of the body, even from the conjunctiva. We shall see that Phosphoric, Sulphuric and Arsenious acids all produce and all check haemorrhages. It is said that they all do this by reason of their astringency. But how can this be so when they act favorably even in the two-hundredth potency?
Another quality of the acids is their tendency to produce pseudo-membranes. Thus we find some of them indicated in diphtheria ; Muriatic, Phosphoric, Sulphuric, and Nitric acids, for instance. Here again caution is necessary. As these acids, particularly the vegetable acids, may cause croupous deposits, do not permit a child convalescing from croup to partake of acid fruits. When the child is so susceptible, any one of these acids may tend to produce this disease again.
We find that all the acids cause a peculiar debility. This is not a simple functional weakness, such as might result from a rather exhausting diarrhoea, such as you find under Cinchona, or such a functional weakness of the nerves as will be curable by Zinc, but it is a debility which arises from defective nutrition, particularly from blood disease. Thus we find them called for in very low types of disease, disease in which blood poisoning is a prominent feature, in typhoid states and in scarlatina, particularly when of a low type, in conditions of exhaustion from abuse of various organs of the body. Thus drunkards who have long been indulging in liquors to excess may be relieved by Sulphuric, Phosphoric, and Arsenious acids.
We find them indicated, too, in diabetes mellitus. The principal acids for this condition are Phosphoric and Lactic acids.
We find, too, that many of the acids are useful in scurvy, particularly when it has arisen from a diet of salty food with deprivation of vegetables. So much for our general review of the acids. We will now begin to speak of the acids in order, and first of all, of Fluoric acid.