This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol1", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
This is made, according to the process of Professor Procter, by dissolving freshly prepared hydrated sesquioxide of iron in a solution of bitartrate of ammonia, then evaporating by means of a water-bath, and drying in thin layers, as in the instance of the last-mentioned salt The equivalent in excess of tartaric acid in the bitartrate unites with an equivalent of the sesquioxide of iron, and a double salt is formed, consisting probably of one equivalent of basic tartrate of the sesquioxide of iron acting as the acid, and one of tartrate of ammonia acting as the base, united, according to Prof. Procter, with four equivalents of water. Or, if tartaric acid be considered as bibasic, with a doubled equivalent, the new salt may be considered as composed of one eq. of tartaric acid and one of each of the bases, and to be, what its name imports, a tartrate of iron and ammonia. When incinerated, the salt leaves 29 per cent of sesquioxide of iron.
It is in brilliant, dark-brown, almost blackish scales, or small, irregular, angular fragments, like those of the Fast India kino; but, by transmitted light, it exhibits a garnet redness. The taste is sweetish, moderately ferruginous, very slightly styptic, and not disagreeable. The salt is very soluble in water. In its reagencies it resembles tartrate of iron and potassa, with which also it is closely analogous in composition, ammonia taking the place of potassa.
In medical properties, as well as in chemical nature, this salt bears a close resemblance to the preceding; and all that has been said in relation to the tartrate of iron and potassa, of its want of unpleasant taste, general mildness, efficiency as a chalybeate in its operation upon the system at large, and inapplicability to the treatment of stomachic and intestinal affections, belongs equally to this salt. It may be used in any case in which it is desirable to impregnate the system with iron, and in which a soluble preparation is wanted. Another advantage of both these salts is that they may be given with the alkaline carbonates, and generally with other saline medicines, without undergoing decomposition. The dose is from five to thirty grains, three times a day. The first quantity mentioned is sufficient to begin with, unless in urgent cases.