It is necessary to change the water in the outer vessel daily. For the first two or three days distilled water should always be used. When this is not obtainable rain water should be employed. When the water shows the absence of chlorides, and the preparation ceases to have a ferruginous taste, the operation may be regarded as finished. The process generally occupies one or two weeks.
“A pig’s bladder, completely filled with the iron solution, securely tied, and immersed in water frequently changed, answers well for making this preparation. The process requires a longer time than with a carefully regulated and properly conducted dialysis, but it entails considerably less trouble. I consider it an advantage to procure the bladder perfectly fresh, as it is then easily cleaned by pure water, and alkaline ley need not be used. Great care is necessary in tying the neck carefully. This can be best accomplished by a few turns of iron wire. Above this may be secured a piece of twine, to suspend the bladder, by means of a stick, or rod, placed on the edge of the vessel containing the water. The bladder should be perfectly full, and immersed altogether in water. The attraction of the solution for the water is so great, that considerable pressure is manifested, and should any parts or holes be in the bladder, the liquid will be forced out, water will take its place, and failure result.”[4]
[4] ‘Canadian Pharmaceutical Journal,’ Oct., 1877.
Pretty general consent appears to have fixed
the strength of the solution of dialysed iron at five per cent. Where it exceeds this, the solution must be diluted with distilled water; and where it falls short of the amount, it will have to be reduced to the required volume by standing it in a warm and dry situation. The employment of much heat must be particularly avoided as it very frequently leads to the destruction of the compound; hence every care should be taken to render the evaporation of the fluid unnecessary.
There seems little doubt that the so-called “dialysed iron” is an oxychloride of the metal. Prof. Maisch[5] believes it to be a very basic oxychloride of iron. On the supposition that the oxychloride and chloride of iron are both present in the liquid put into the dialyser, the origin of the oxychloride admits of easy explanation:—The chloride being a crystalloid, diffuses through the septum into the outer water, and thus becomes separated from the oxychloride, which being a colloid, and incapable of a passage through the membrane, remains in solution in the dialyser.
[5] Ibid., Oct., 1877.
The comparative freedom from taste and easy assimilation of the oxychloride of iron render it a valuable therapeutic agent. The dose of the five per cent. solution is 15 to 50 drops daily, in divided doses. Syrup forms a pleasant vehicle for its administration.
Dialysed iron has been successfully employed in a case of arsenical poisoning. The ‘American Journal of Pharmacy’ for January, 1878, contains an interesting paper by Dr Mattison detailing a series of experiments, which conclusively prove its value as an antidote to arsenic. Dr Mattison recommends the administration of the iron to be immediately followed by a teaspoonful or more of common salt.
IRON FI′′LINGS. Syn. Ferri ramenta (Ph. L. 1836). Ferri limatura (Ph. E.), Ferri scobs (Ph. D.). The usual method of preparing iron filings for medical purposes has been already noticed; the only way, however, to obtain them pure, is to act on a piece of soft iron with a clean file. The Fr. Cod. orders them to be forcibly beaten in an iron mortar, and to be separated from oxide and dust by means of a fine sieve, and from the grosser parts by means of a coarse hair-sieve.—Dose, 10 to 30 gr., in sugar or honey, as a chalybeate; in larger doses it is an excellent vermifuge, especially for ascarides or the small thread-worm.