REMARKS ON SOME OF THE MERCURIAL COMPOUNDS. 49 
presence of the black or protoxide of mercury ; at present, 
however, the change is generally attributed solely to the me- 
chanical division of the metal, which in this state is sup- 
posed to be capable of acting on the system " fyc. 
In a paper communicated to the Journal of Pharmacy, 
(Philadephia, 1829) by Mr. Allison, it is attempted to be 
proved: 
1st. That the presence of the adhesive substances used 
in the preparation of the mass, "effectually prevent the con- 
tact of the air with nearly all of the metal employed." 
2d. That the time used in its preparation is too brief for 
any action to take place even if the first objection were re- 
moved, (no doubt alluding to the fourteen years which Dr. 
Duncan relates that Boerhaave exposed his mercury to the ac- 
tion of a windmill,) and finally comes to the conclusion, that 
the popular idea of the inertness of metallic mercury on the 
system is erroneous. 
In opposition to this we have testimony of much more 
weight, and founded on the authority of the best chemical au- 
thors. Ure, Eberle, Paris, Coxe, Murray, and a number of 
others, confirm the opinion generally received, that mercury 
in its uneombined state has no action on the system, and the 
authors of the United States Dispensatory declare, " that it 
is considered to be inert." No metal can have any action on 
the system, or form any salts until oxidation first occurs, 
and those writers whom we have quoted assert that it is difr 
ficult to oxidate mercury at common temperature; again, me- 
tallic oxides are only active, inasmuch as meeting with the 
free hydrochloric, acetic or other acids in the stomach they 
then form soluble and active salts. In order then to prove 
that mercury has any action on the system in its metallic 
state, it must first be proved, that acids act on pure ?netals, 
which is utterly impossible; next, that mercury is an except 
tion to all the rest of the class of metals in its action on the 
human system. 
On what principles of chemical reasoning can it be asserted 
VOL. VIII. — no. i. 7 
