954 
THE PHARMACEUTICAL JOURNAL AND TRANSACTIONS. 
[May 31, 1873, 
chemical properties of the various iron combinations and 
describe a new series of tasteless ferruginous compounds. 
Iron has been used in medicine, it may be said, from 
tune immemorial. Metallic iron, green copperas, iron 
rust, carbonate of iron, bole armenia, etc., are mentioned 
in the oldest authors on medicine and pharmacy. It 
seems also that in former times little importance was at¬ 
tached to the peculiar form in which iron was administered. 
Some fifty or sixty years ago, however, a decided prefer¬ 
ence began to be shown for metallic iron, finely commi¬ 
nuted, and for the protosalts of iron. It was thought, 
then, that the easy solubility of those preparations in the 
stomach was a great advantage, and that theory gave rise 
to a number of officinal remedies like iron by hydrogen, 
Vallet’s mass, protoiodide of iron, etc., etc., well known 
to all pharmacists. 
But of late years, especially since the discovery of the 
citro-ammonical pyrophosphate of iron, by Robiquet, my 
old master, salts of sesquioxide of iron have been steadily 
growing into favour. It has been argued, with reason, 
that, since iron in human economy is invariably found in 
the shape of sesquisalts, such compounds should be pre¬ 
ferred to all others whenever iron is indicated. I may 
add, also, that it is always in the form of sesquisalts that 
iron exists in all vegetable and animal substances which 
compose human food, and that metallic iron or its proto¬ 
salts cannot be mixed with the simplest aliments without 
completely decomposing them. Protoxide of iron is as 
unyielding as it is unstable : when you have combined it 
with strong acids you can go no further with its salts : 
you can do nothing with them, not even an alum. Ses¬ 
quioxide of iron, on the contrary, is a perfect Proteus ; 
sometimes a base, sometimes an acid, it is always ready to 
enter some combination or other on the slightest provoca¬ 
tion. 
In a paper published some time ago I demonstrated that 
nearly all the insoluble sesquisalts of iron could be com¬ 
bined with the alkaline citrates, forming soluble and 
tasteless compounds, to which I gave the name of quadruple 
citrates. 
Since then, further experiments have shown me that 
other vegetable salts, besides the citrates, possessed also 
the same property, and that not only the insoluble but 
also the soluble sesquisalts of iron could form similar 
combinations. 
In other words, I may lay down this rule :— All the 
salts of sesquioxide of iron, without exception, soluble or 
insoluble , form combinations with all the alkaline citrates, 
tartrates, and oxalates. Such combinations are invariably 
green, whatever may be the colour of the iron salt; they 
are all soluble in water, nearly insoluble in alcohol; they 
are all free from ferruginous taste, all perfectly stable, 
and miscible with preparations of Peruvian bark without 
decomposition. In all of them the presence of iron is so 
disguised as not to be detected by chemical reagents, 
unless after the addition of strong acids or sulphuretted 
hydrogen, both of which destroy the combination. 
In other papers I have described the soluble compounds 
obtained in combining the phosphate, hypophosphate, 
valerianate, and arseniate of iron with the alkaline citrates. 
In this I will merely describe the tasteless combinations 
of the alkaline citrates with iodide, chloride, sulphate, and 
nitrate of iron. 
Tasteless Iodide of Iron * 
This is, no doubt, the most important of the whole 
series, both therapeutically and chemically ; therapeuti- 
cally, because iodide of iron is admitted to be the best of 
all iron combinations; chemically, because all the reactions 
happening during its preparation are so remarkable and 
so easy to follow with accuracy as to be likely to give a 
key to the real composition of the rest of the series—a 
The tasteless iodide of iron has been patented, but with 
no intention of interfering with any druggist who wishes 
to make it himself for his own dispensing. 
result which can hardly be obtained with any of the other- 
similar combinations. 
The salt is obtained in the following manner : 126 - 3 grs.. 
(1 eq.) of iodine are first combined with metallic iron, in the 
usual way to obtain the protoiodide of iron ; this is filtered, 
and 63 grs. (| eq.) of iodine are dissolved into it. Then, a 
solution of 201 grs. (1 eq.) of citric acid saturated with a 
fixed alkali, such as potassa, for instance, is added by 
small portions to the sesqui-iodide of iron. The ferru¬ 
ginous solution which is at first of a ruby red colour and 
has a strong smell of iodine, becomes lighter by degrees, 
till, as the last drop of citrate is added, it takes a bright- 
apple green colour ; at the same time, all smell of iodine, 
all taste of iron have disappeared; the solution strikes no¬ 
colour on starch paper, and gives no precipitate with either- 
tannin or ferrocyanide of potassium. It may be then 
evaporated at a low heat, with gentle stirring, to dryness, 
when it gives a green mass formed of very small acicular 
crystals, looking somewhat like cauliflowers. It is taste¬ 
less, perfectly stable, unless exposed to direct sunlight, 
and may be exhibited, in the shape of syrup, elixir, solu¬ 
tion, tincture, pills, etc. The dose of it need not be more 
than one-half of that of the protoiodide of iron, as it is 
absorbed much more readily. 
Chemically, this iodide of iron seems to be a combina¬ 
tion in which sesqui-iodide of iron plays the part of an acid 
and the alkaline citrate that of a base ; but the subject 
requires further investigations before it can be decided 
with complete certitude. 
The other alkaline citrates may be used instead of 
citrate of potassa; similar combinations may also be 
obtained with the alkaline tartrates, oxalates, and malates, 
but none are so tasteless, and especially none so stable as 
the one just mentioned. 
I must add a few words on this subject which is a most- 
important one, for the same remarks may be applied to 
all the other analogous iron combinations, pyrophosphate 
included. On reading the above process, some may think 
that, after all, the product is only a mixture of citrate of 
iron, iodide and iodate of potassium. But, aside of the 
fact that the different ingredients are not in proportion to- 
form such combinations, chemical tests show that such is 
not the case. Citrate of iron, for instance, is of a ruby 
red colour and turns immediately ink black on the addition 
of tannin, while tasteless iodide of iron is bright green and 
is not coloured black by tannin, but only turned to a light, 
purple hue, after some time. Iodide of potassium dissolves- 
iodine freely ; the new salt dissolves it but sparingly, un¬ 
less when in a concentrated solution. Iodate of potassium 
is coloured red by solutions of morphia ; no colouration is 
produced by them in solutions of the new salt. This last 
reaction is important, as iodate of potassium is deemed 
poisonous by some physicians. 
Tasteless Chloride of Iron. 
Sesquichloride of iron, the salt which enters into the 
preparation generally known as tincture of muriate of 
iron, has the property of forming combinations precisely 
similar to those of the sesqui-iodide. If an alkaline citrate 
be added to a solution of sesquichloride of iron, in the- 
proportion of two equivalents of the former to each three 
equivalents of chlorine, a new salt will be obtained of a 
green colour, quite tasteless, and miscible with vegetable 
preparations such as infusions of bark, quassia, etc., without 
change or discolouration. 
This tasteless muriate of iron may be dissolved in diluted 
alcohol in the proportion required by the Pharmacopoeia of 
the United States ; it forms, then, a tincture of muriate 
of iron, which is as superior to the old one as a civilized 
man is above a barbarian. Its effects, I know, from 
experience, are fully equal to those of the officinal tincture. 
I cannot give the exact weight of citric acid required 
for a given quantity of the officinal tincture of muriate of 
iron, on account of the great variation in the strength and 
acidity of that preparation, but, on an average, 120 to 140 
grains of citric acid saturated with either soda or ammonia 
