46 REMARKS ON SOME OF THE MERCURIAL COMPOUNDS. 
ART. VI. — REMARKS ON SOME OF THE MERCURIAL COM- 
POUNDS. By James Hamilton, M. D., Baltimore. 
There are few medicinal agents embraced in the Dis- 
pensatory, more frequently employed in disease than the 
compounds of mercury, and of them it is to be regretted many 
are employed without a due knowledge of their composition, 
or the principles on which they act. 
In this remark, the preparations of Pil Hydrargyria Hy- 
drargyrum cum cretd and Unguenta Hydrargyria are par- 
ticularly alluded to, and as such are intended to be the sub- 
ject of this article. 
The cause of the efficacy of these preparations has led to 
the adoption of many opinions, reducible however to two, 
viz. the presence and agency of the protoxide of mercury, or 
metallic mercury, in a minute state of subdivision; each of 
these has been upheld and supported by numerous contribu- 
tors to periodicals, some teeming with contradictions and as- 
sertions which can only be attributed to ignorance of the prin- 
ciples of chemistry or a desire to win popular esteem as au- 
thors ; it is not to be wondered at, then, that even at the pre- 
sent day this question is acknowledged to be unsettled, inas- 
much as but little positive proof has been brought forward 
by many of those who have thus far enlightened the medical 
world with their opinions. 
As the question is one of undoubted interest to the intelli- 
gent physician, and is based on some of the properties of mer- 
cury itself, these necessarily will require an examination first, 
in order to relieve us of the discrepancies which appear in 
many of the articles already published on the subject. 
The metals may be divided into two classes as regards the 
changes to which they are liable under common circum- 
stances, some being oxidized at the common temperature; 
others remaining unaltered, and mercury in this respect is not 
sufficiently known to be classed in either; Turner, Green, 
