90 
ON PREPARED IRON. 
driven off in the form of vapor ; and the process must be 
continued until moisture ceases to be given off, which may 
be tested by holding a smooth polished surface of metal or 
glass at the farther extremity of the barrel. The gun-bar- 
rel should be closed at both ends by a cork, through which 
at one end an escape tube of glass or metal is passed, and 
at the other, the tube leading from the gas generator. It 
is necessary to observe the test, as to the escape of vapor, 
to insure the perfect reduction of the oxide of iron. 
It may also be prepared by precipitating the protosulphate 
of iron in solution with oxalic acid. To a saturated clear 
solution of two parts of crystallized copperas, add one part 
of crystallized and pulverized oxalic acid, with constant 
stirring, until the whole assumes a yellow color; after stand- 
ing a short time, stir again, and set it aside for twenty-four 
hours. The yellow oxalate is then filtered off, dried, and 
exposed to a red heat in a crucible, when the oxalic acid, 
by decomposition, carries off the oxygen of the iron, leaving 
it in a finely divided metallic state. Fe 0-fC 2 3 =Fe-f 
2C C 2 . With a lower heat the oxalate will still decompose, 
but ithen the iron is so finely divided, that when poured 
through the air, even if cold, it attracts oxygen so rapidly 
as to take fire, and burn to red oxide. The same may take 
place with the iron reduced by hydrogen, if the operation 
be conducted at too low a temperature, 
M. A. Raciborski ascribes its activity to the fact that it 
more easily combines with the acids with which it comes in 
contact in the stomach, and is thus sooner conveyed into the 
circulation. 
It may be administered in almost any form. MM. Que- 
venne and Micmelard recommend its administration in the 
forms of pastilles, made with chocolate, sugar, and gum ; 
and remark, that when thus mixed, they present no peculiar 
appearance, and their taste differs so little from that of or- 
dinary chocolate, that it is necessary to have the attention 
