48 REMARKS ON SOME OP THE MERCURIAL COMPOUNDS. 
this, as I have been assured by those who are compelled to 
resort to pure mercury, that simple contact with oils or other 
viscid matter has this effect to such an extent as to render it 
useless to them until purified by distillation, and all who have 
been in the habit of using pure mercury in their manipula- 
tions, must have observed the rapid oxidation whenever 
brought into contact with foreign substances. 
PIL HYDRARG-YRI. 
This mercurial compound is as frequently employed as per- 
haps any other, though the results often obtained from its use 
are not equal to what are anticipated. In the United States 
and London Dispensatories, the mercury is triturated with 
confection of roses and liquorice root; in the Edinburg with 
conserve of roses and starch ; in either case the materials are 
triturated until all appearance of metallic globules has ceased, 
and the mixture has attained that blueish-gray appearance 
which has given rise to the name of blue mass. 
A diversity of opinions are entertained with regard to the 
cause of the action which results from its use, some attribut- 
ing it to the presence of the protoxide of mercury, others to 
mercury in a very minute state of subdivision. Let us ex- 
amine the grounds which the latter have for this supposi- 
tion. 
Mr. Carpenter, in a memoir on " the Extinction of Mer- 
cury by Trituration," (Philadelphia, 1827,) has been at con- 
siderable pains to attempt to prove that the mercury is only 
in a minute state of subdivision and not oxidized, in which it 
need only be said he has failed. 
Laugier (Cours de Chimie, torn. 11, page 310,) sa)^s, "on 
est fonde a croire aujourdhui que ce changement de couleur 
tient seulement a l'extreme division desparties du me- 
tal," &c. 
The United States Dispensatory, (1839,) says: "it was for- 
merly thought that the metal was oxidized in the process, and 
that the medical activity of the preparation depended on the 
