142 
ON AN ANTIDOTE AT ONCE FOR 
We found tliat 80 grs. of peroxide of iron in the form of hydrate, obtained 
by precipitation with carbonate of soda, absorbed 10 grs. arsenious acid from 
solution. What iu this case would have been the result, supposing this had 
been an actual case of poisoning with arsenious acid ? 80 gr's. of peroxide 
of iron, in the form of perchloride, would have required 3 equivalents, or 432 
grs. of carbonate of soda. The result of the double decomposition between 
the perchloride of iron containing 3 equivalents of chlorine and the 3 
equivalents of soda in the carbonate of soda, would have been 3 equivalents 
of chloride of sodium, or 175*5 grs., i.e. less than half an ounce of common 
salt, which, as an emetic, would actually have assisted the recovery of the 
patient, and therefore its exhibition along with the antidote could only have 
acted beneficially. 
As we have found by innumerable trials that 80 grs., or 1 equivalent of 
peroxide of iron, absorbs 10 grs. of arsenious acid, it is necessary to find how 
much of the solution of the perchloride of iron is required to give that 
quantity. The calculation is easily made : 80 grs. peroxide of iron contain 
56 grs. of iron, and as 10 fluid oz. of the solution contain 2 oz. or 875 grs. of 
metallic iron, the quantity required is given by the following proportions:— 
875 : 10 : : 56 : x — Q'64. The quantity of the solution of perchloride of iron 
containing 56 grs. of metallic iron, or 80 grs. of peroxide, is therefore 0'64 
oz., or if of an oz., or exactly 5 fluid drachms and 7 minims. 
The quantity being thus known, when the antidote is required, 307 minims 
of the solution are to be measured out, mixed with 1 or 2 ounces of 
water in a measure or beaker, and 1 ounce of crystallized carbonate of soda 
having been dissolved in about a couple of ounces of warm water, by rubbing 
up in a clean mortar, it is poured into the solution of iron, and the mixture 
stirred with a glass rod till the effervescence ceases; the pulpy hydrate is 
then ready for exhibition. 
The moment the antidote has had time to mix with the contents of the 
stomach, it will have absorbed arsenious acid to the extent of 10 grs. Should 
more than that quantity have been taken, it becomes a question how much 
of the antidote may with safety be given, in the form recommended. It 
appears to us that a large quantity could be given with perfect safety. If 
the decision should be different, it would then be necessary to prepare the 
hydrated oxide of iron in the way recommended by Bunsen, and for the pre¬ 
paration of which there would be abundance of time, on account of the im¬ 
mediate effects of the poison having been effectually counteracted. 
The solution of perchloride of iron is admirably adapted for the preparation 
of the hydrated peroxide. 10 fluid oz. give 1256 grs., or nearly 3 oz. of 
peroxide. Supposing 3 fluid oz. of the solution be taken to prepare the 
hydrate ; pour this quantity into a convenient vessel for precipitation, a tall 
precipitating-glass would be best, add from five to ten times its bulk of pure 
water, then add liquor aramonia until, after brisk agitation, it smells dis¬ 
tinctly of the volatile alkali; let the precipitate settle ; pour off the clear 
liquid, and mix in a fresh quantity of water; let the precipitate settle a 
second time, then pour off the liquid as before; after repeating this opera¬ 
tion several times, it may be considered sufficiently washed, but it may be 
better washed by now filtering, and if the hydrate has been thrown down 
from a warm and concentrated solution (which we have found does not pre¬ 
vent its antidotal action), the washing on the filter is not by any means te¬ 
dious. The hydrate may easily be not readv for use in about an hour. The 
hydrate thus obtained is a most effectual antidote, and can be administered 
safely in almost any quantity. 
When we turned our attention to this matter, we were in the belief that 
the hydrated oxide of iron would only act as an antidote to arsenious acid in 
