PRESERVATION OF PROTIODIDE OF IRON. 
15 
of iron, and the sequel will show how far the suggestion 
has been realized. 
As it is our duty at the time we are pursuing a course of 
investigation, to note all the phenomena that offer, perhaps it 
will be well to give an idea of the relative protecting power 
of several saccharine substances, so as to be able to appre- 
ciate their importance, and to ascertain, if possible, some ge- 
neral principle which will account for the variation in their 
protective power. 
The substances tried were sugar of milk, manna, cane sugar, 
honey, and uncrystallizable sugar. 
The uncrystallizable portion of honey and molasses was 
obtained by mixing the honey or molasses with twice its 
weight of alcohol. The cane sugar precipitates, if molasses is 
employed, and the crystallizable honey, if honey is used, and 
by evaporating the solution, the preparation is obtained free 
from alcohol. They should be decolorized as much as possi- 
ble, by boiling with animal charcoal, before being used. 
1st. The power of sugar of milk and manna in protecting 
the iodide is very slight, although they each may possess the 
property in a limited degree. The trials which were made, 
however, offer convincing proof of their inadequacy to per- 
form the purpose in view. 
2d. Three drachms of the solution of protiodide of iron 
was mixed with one drachm of simple syrup, and placed in a 
vial exposed to light and air. In a similar vial alike quantity 
of the solution was placed without the addition of syrup, and 
equally exposed to air and light. At the end of forty-eight 
hours the saccharine solution remained transparent, possessing 
its original color, while the other had acquired a brownish 
hue. They remained thus exposed to air and light for two 
weeks — at the end of that period the unprotected solution 
had deposited a considerable quantity of peroxide of iron, 
and was strongly charged with free iodine. The saccharine 
solution was also colored, but in a very slight degree, with an 
equally small deposit of ferruginous oxide, but we must be 
