106 M. Vogel on [Frs. 
a blood red solution; and both of them give the same colour to 
the persalts of iron. mie 
The red solutions, produced by both of these acids, lose their 
colour on the addition of acids, alkalies, protomuriate of tin, and 
the solar rays. 
The disappearing of the red colour by the sun’s rays is owing 
to the peroxide of iron being changed into protoxide ; for ammo- 
nia throws down a reddish precipitate from the red solution ; 
but a green precipitate (protohydrate of iron) from the liquid 
rendered colourless by the solar light. 
When the liquids rendered colourless by the sun are placed in 
a dark place, but exposed to the air; or better, if they be 
laced in contact with nitrous acid in the state of vapour, the 
blood red colour appears again; because the iron is again con- 
verted into peroxide. 
Writing with common ink becomes red, when plunged into 
sulphuretted chyazic acid, as it does when plunged into meconic 
acid. 
But the analogy between these two acids does not go further. 
Solution of gold deprives the compound of sulphuretted 
chyazic acid and peroxide of iron of its red colour; but it pro- 
duces no alteration in the solution of peroxide of iron in meconic 
acid. . 
Finally, meconic acid is solid, crystallizable, and capable of 
subliming, while sulphuretted chyazic acid is a liquid, and a 
violent poison. 
Dr. Scemmering made a set of experiments on dogs with 
sulphuretted chyazic acid, meconic acid, and morphia. We 
cannot enter into a detail of the numerous experiments which 
he made on this subject. As a paper on the subject will be 
published in Schweigger’s Journal, we shall confine ourselves 
here to the following observations which contain the general 
results. 
Outline of the Physiological Experiments. 
Concentrated chyazic acid occasions sudden death, when 
administered in the quantity of half a gros. When the acid is 
much diluted with water, and given in repeated doses, it acts 
on the organs of respiration, produces convulsions, and death 
ensues more slowly. 
A small quantity of this acid affects the respiration. The acid 
is voided in the urine, without producing permanently bad 
consequences. 
A dog, upon which the diluted acid was made to act for 24 
hours, and which died in consequence, was opened. The pre- 
sence of the acid could be detected in the blood, and still more 
easily in the urine. 
Sulphuretted chyazate of potash, administered in the same 
