280 
Facts and Observations. 
THE STATE OE MERCURY IN HYDRARGYRUM CUM CRETA. 
Dr. Redwood has ascertained that the conditional state 
of the metal mercury in the above compound varies. It 
should be only a mixture of chalk and finely divided mercury; 
but being made by long-continued trituration, it is often the 
case that both the protoxide of the metal and the peroxide 
are present. To this fact he attributes the difference in 
action of different samples of the compound examined by 
him, some of them being harmless, while others, if not 
poisonous, were dangerously active compounds. The follow¬ 
ing table gives the result of his experiments: 
Hg. 
HgO. 
Hg0 2 . 
1 . 
. . 371 
0-4 
a trace in one hundred parts. 
2 . 
. . 325 
3-74 
1-45 
)) 
3 . 
. . 27*9 
4-99 
5-18 
4 . 
. . 20*4 
13T 
4-86 
5 . 
. . 21*7 
7-9 
8-85 
G . 
. . 13T 
11-64 
14-25 
According to Pereira, the protoxide of mercury is one of the 
least irritating of the mercurial preparations, and therefore 
does not produce much disorder in the alimentary canal. 
The binoxide, however, is a powerful irritant, and when 
taken, often produces vomiting and purging. Large doses 
excite gastro-enteritis, and Orfila found that this, the red 
oxide, obtained by precipitation from four grains of corrosive 
sublimate, killed a dog in eighteen minutes. 
The blue pill and mercurial ointment are stated to be 
compounds into which only the finely divided metal enters ; 
yet is it not possible, as the same mechanical means are 
resorted to for making them, that the mercury may also in 
them be sometimes oxidized? Moreover, is it not well 
known that, by the addition of substances rich in oxygen, 
the hilling of the mercury has been more quickly brought 
about? Further, it has been ascertained that, if the sub- or 
protoxide of mercury be otherwise obtained, and mingled 
with conserve of roses, so as to form the first named, and 
lard to form the second, equally efficacious compounds have 
resulted. 
