MEDICINAL USES OF 'Enos COMPOUNDS. Iron itself and a number of its compounds are used in medicine in the form of various preparations; in the stomach all such compounds are con verted into ferric chloride, and to a small ex tent into ferrous chloride. One of the best medi cinal compounds of iron is ferric chloride, the evil effects of whose strongly acid properties may be avoided by the addition of bicarbonate of sodium. Another way to avoid the undesir able effects of acid compounds of iron is to ad minister them in the form of coated pills which may pass through the stomach unchanged, the acidity being then neutralized in the alkaline juices of the intestine. The constipating effect of iron compounds is well known, but is gen erally somewhat exaggerated; this eflect may be readily avoided by the use of suitable purgatives. To avoid indigestion, iron compounds should not be taken shortly before or after meals. In the mouth, iron salts may (if acid) attack the enamel of the teeth, and by combining with sul phur (from food or the tartar of the teeth) form a black deposit of ferrous sulphide on the teeth and the tongue. For these reasons iron preparations are usually administered through a glass tube, and the mouth is to be carefully rinsed immediately after taking the dose.
Besides constituting the best-known local astringents for external iron salts are extensively used as a remedy for many forms of anfemia and the conditions caused by them, the best results being obtained by the use of ferrous sulphate and ferric chloride (the latter together with some glycerin). Iron salts have also been given with success in diphtheria, ton silitis, and other forms of sore throat, as well as in erysipelas. In anemia they have the effect of restoring the number of corpuscles and the normal amount of hemoglobin in the blood. The fact that this takes place appears very re markable in the light of a great deal of evidence which tends to show that no iron is actually absorbed into the system. We have seen above that in the stomach a]] iron salts are trans formed into ferric chloride. On reaching the intestine the chloride is transformed into ferric hydroxide, and subsequently the latter is in turn transformed into the black sulphide and tannate of iron, which are voided with the frees. All of the iron taken is thus voided, and none passes into the urine. On the other hand, when
injected into the blood, even in very moderate quantities, iron salts produce symptoms of poi soning. The question therefore arises: In what manner do iron salts act in relieving anemia? Definitely this question has not yet been an swered. According to a theory advanced by Runge, the iron normally present in the blood enters it in the form of complex organic iron compounds that are contained in food. That iron in some form or other necessarily enters the blood is evident. if we remember that the amount of iron in the body of a child increases with age. Now, according to Runge. the alkaline sulphides that may he present in the intestines are capable of depriving the iron compounds of food of their iron. the resulting sulphide being of course incapable of absorption. But if suffi cient quantities of iron are taken internally. the alkaline sulphides are decomposed and the or ganic iron of the food becomes available. The amounts of iron required depend of course upon the amount of alkaline sulphides in the intes• tines, and this is why it may be found necessary to administer as much as IS grains a day to an anaemic woman whose body. in a normal state. contains altogether about 30 grains. A strong argument in favor of Bunge's theory of the in direct action of iron is found in the fact that manganese. copper. and certain other substances not at all present in the blood are almost as efficient as iron in curing anemia.
Ferric chloride. the most important medicinal salt of iron. is usually administered in the form of its tincture, which contains about 3.23 per cent. of iron, corresponding to about 0.5 per cent, of anhydrous ferric chloride. The tincture is prepared by making up 250 parts of the offi cial aqueous solution of Eerie chloride to 1000 parts with alcohol. Pcrric hydroxide with may ntstu is known as 'arsenic antidote,' being an etleelite remedy for poisoning with arsenic. The antidote may be best prepared by gradually adding 10 parts of magnesia in water to 50 parts of ferric hydroxide in water, and shaking the mixture vigorously. It should be prepared immediat(ly before using. and should be given repeatedly in large doses. Iron salts should never be given together with any preparation containing tannic or gallic acid.