PRESERVATION OF PROTIODIDE OF IRON. 
17 
with filtered starch water; to one was added a few drops of 
the protected solution, to the other an equal quantity of the 
unprotected solution of iodide of iron. At the end of twenty- 
four hours the presence of free iodine was rendered evident 
in the latter by the blue color acquired by the starchy solu- 
tion, whereas the former remained colorless. 
8th. Thinking, notwithstanding the present protective 
power of the agents, that the increased temperature of summer 
might cause fermentation, and thus render the protector 
worse than useless, four ounces of the solution, protected 
with uncrystallizable honey, was placed in a vessel of water, 
the temperature of which varied from 80° to 100°, Fah., for 
nine days. At the end of this period no signs of fermenta- 
tion were evidenced, and no free iodine existed in the solu- 
tion. The exposure to heat was then discontinued, under the 
impression that if disposed to ferment, the solution had ample 
time to give notice of it. 
It remains now to offer a formula for the proposed prepa- 
ration. The strength of the following is that proposed to be 
adopted at the late convention on the Pharmacopoeia: 
Jfc. — Iodine, . . . . . 3xi. 
Iron filings, .... 3iv. 
s y r '-p> ; 
Uncrystallizable honey, or 
Uncrystallizable sugar, . . giv. 
Distilled water, a sufficient quantity. 
Mix the iodine with eight fluid ounces of the distilled water, 
and gradually add the iron filings, stirring constantly; then 
apply a gentle heat until the solution shall have acquired a 
light green color, or shall not give a blue color to the solution 
of. starch, then add whichever of the three protecting sub- 
stances may be chosen, and continue the heat a short time, and 
filter. Lastly, wash the filter with as much distilled water 
as will make sixteen fluid ounces of solution of protiodide of 
iron. 
When either sugar or honey is used, the color of the sola- 
VOL. VI. NO. i. 3 
