116 
ON THE PROTO-IODIDE OF IRON, &C. 
ioduretted, is proven by the odor of the compound, and the 
blue color produced with starch. The deep blue precipitate 
produced by the yellow cyanide of potassium and iron, de- 
monstrates that the iodide is partly, if not wholly in a state of 
per, and not proto-iodide. As to the presence of the sesqui- 
oxide of iron, it does not naturally belong to it, but is the ne- 
cessary result of the change which the proto-iodide undergoes 
from the action of the air. When we keep a solution of proto- 
iodide only two or three days, we percieve this oxide com- 
mencing to form as a reddish deposit. M. Dumas supposed 
that it was an insoluble combination of iodine and sesquioxide 
of iron. 
The foregoing remarks suffice to prove that the iodide usually 
employed in Pharmacy under the name of proto-iodide of 
iron, is not a proto-iodide, but a mixture varying in composi- 
tion, and consequently in therapeutic effects; it differs then 
essentially from the proto-iodide of iron, the administration of 
which has been followed by advantageous results in the 
treatment of phthisis pulmonalis. I may add that the for- 
mer cannot replace the latter, clinical observation having 
proven that the least alteration in the colorless proto-iodide 
will suffice to weaken its medicinal properties, and to 
communicate an irritant action, which totally changes its 
effects. 
With these explanations I proceed to the preparation of the 
proto-iodide of iron, and to the formulas of which it is the 
basis. 
In combining the elements of the preparations which have 
been made into formulas, the object was to facilitate the means 
of varying the administration of the proto-iodide of iron, as 
well as to insure to this new remedy a perfect state of preser- 
vation.* In all these preparations, the normal solution ex- 
cepted, the proto-ioduretted compound is free from contact 
*I have proven, by clinical observation, this important fact, that the 
proto-iodide of iron, under whatever form it may be given, acts in an iden- 
tical manner, whenever it has not suffered any change. 
