This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol2", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
Chlorine, in its various compounds, seems to have a certain controlling influence in their operation upon the system, giving them, in some degree, a similarity of character in this respect, though much modified by the peculiar properties of the base, or of other associated bodies.
* Use of iodine with Aliments. Under the impression that, if introduced into the system in minute quantities with alimentary matters, iodine would produce its effects in the most natural method, and with the least possible chances of injury, M. Boinet incorporates it with bread, cakes, chocolate, wine, beer, etc; preferring, for the purpose, the form of iodine found in nature, as fuci, marine and cruciferous plants, and the iodine salts from mineral waters. The medicine is thus introduced insensibly into the system, and is said to produce extraordinary effects, after some months of treatment, in all those scrofulous affections in which iodine has been found useful. The iodine seems to be considered by M. Boinet as an aliment, essential to health, and is given, rather as food than as medicine, to supply a presumed deficiency of it in these affections. (Ann. de Thérap., 1859, p. 183.) - Note to the second edition.
A certain amount of the chlorides in the system, and especially of the chloride of sodium, is absolutely essential to health, and probably to life. They have been supposed to be useful by affording muriatic acid to the process of digestion; but this is assuredly not the whole, nor probably the most important office they perform in the animal economy. What precisely that office is, we do not know; but it has been observed that a deficiency of common salt conduces to a low state of the vital powers, and a depraved condition of the blood, disposing to a kind of malignancy in disease, as exhibited in the low typhous state of fever and inflammations, gangrenous affections, passive hemorrhages, etc.
It is in such affections, and in those of a strumous or scrofulous nature, that the compounds of chlorine have been found beneficial, or at least have been supposed to be so. To correct the state of the blood and the vital forces in that peculiar depravation above mentioned; to act as de-obstruents or resolvents in strumous swellings, and other indurations, consolidations, or tumefactions; and to obviate generally the effects of the scrofulous diathesis, are the common purposes to which they have been applied, and to which experience would seem to have appropriated them, altogether irrespective of their resemblance in chemical character, and, to a certain extent, even before this resemblance was known. This will be rendered obvious in the remarks on the several preparations which follow. it would seem scarcely possible that there should have been such a practical appropriation of these varied bodies, based upon experience, without some real ground in truth; and a rational explanation of the fact is offered by the common chemical tie between them.
Chlorine itself, in its uncombined state, probably never enters the blood. its chemical affinities are such that it would, in all probability saturate itself very speedily, upon contact with any of the fluids of the body, either with hydrogen or one of the alkaline or earthy metals, forming muriatic acid or chlorides, and possibly chlorates; and whatever constitutional impression it is capable of producing, independent of its topical action on the surface of application, must be ascribed to these or other combinations.
As the several medicinal substances containing chlorine have, for the most part, peculiarities of operation distinct from what they all have in common, it will be best to consider them separately. Some of them, as muriatic acid, nitromuriatic acid, chloride of iron, etc., have been treated of under other heads; but, if the reader will refer to what has been stated under each of these, he will note some allusion to a peculiar alterative power possessed by them, as by the muriatic acid in malignant fevers, the nitromuriatic in chronic hepatitis and certain deranged states of the blood, and the tincture of chloride of iron in erysipelas. I shall notice particularly here only those which have not found a place in other classes.