60 
SELECTED ARTICLES. 
there remains 133 grains, or 2.8 grains per pill, if there be 
made 48 of them, and 1.4 grains if the mass be divided into 
96 parts, as I have proposed. 
It is, moreover, easy to be convinced that a large excess of 
carbonate of potassa exists by dissolving a few of the pills, 
and filtering the liquid. This offers an alkaline reaction, and 
effervesces briskly with the acids. It is entirely colorless, 
and does not retain in solution an atom of iron, the metal 
being found in the precipitate in the state of carbonate or hy- 
drated oxide. So that the following is the true composition 
of Blaud's pills. 
They contain, — 
Sulphate of potassa, 
Carbonate of potasssa, 
Hydrated carbonate of iron, more or less suroxidated 
and decomposed. 
The use of these pills differs from that of the hydrate of 
iron, prescribed by physicians generally, under the name of 
subcarbonate of iron, not only in consequence of the pre- 
sence of sulphate of potassa, as is supposed by some persons, 
but also of carbonate of potassa; and because the iron is pre- 
served for a long time in the pills in a lower state of oxida- 
tion, and partly in the state of a carbonate, which, in fact, 
renders it more readily absorbed. 
Since this medicine has been employed, many practitioners 
have substituted in their prescriptions the bicarbonate of 
potassa, for the simple carbonate; and I have not hesitated to 
direct this formula in my Pharmacopee Raisonnee, torn 1, 
p. 383, because, in fact, it presents greater advantages than 
the other. 
1. By the avoidance of a very alkaline salt, an excess of 
which may not prove beneficial to the stomach. 
2. By the formation of a double carbonate of potassa and 
iron, which is, of all the compounds of iron, the most fitted 
for absorption by the economy, for it is not only soluble, but 
not astringent. 
