REMARKS ON SOME OP THE MERCURIAL COMPOUNDS. 51 
it becomes insensibly so incorporated, (if the term may be 
allowed) in the system, that a miner on passing a piece of 
gold or silver coin between his hands, covers it at once with 
an amalgam, and still suffers no inconvenience from being 
subjected to its influence. In the latter case the mercury must 
be in a most minute state of subdivision, to such an extent as 
not to be visible on the surface, and consequently in a state 
best calculated to act on the system. 
The proof that Mr. Allinson has attempted to bring forward 
is easily refuted from the evidence which has already been 
adduced: 1st, those agents which he seems to think prevent 
oxidation by protection from contact with air, have been 
shown by the best authority to be the very cause of the 
rapidity of oxidation which ensues, and the 2d objection, viz. 
the time not being sufficient for the oxidation of the metal, is 
removed by the same means. 
In his experiments on blue mass to detect protoxide of 
mercury, he states, " I boiled it in successive portions of dis- 
tilled water until all the soluble matter was dissolved, then 
digested the residue in acetic acid with heat; no acetate of 
mercury was found;" but this is not astonishing, as Turner, 
whom he has quoted in his article, states, that the protoxide 
" is easily affected by heat by the direct solar rays, and even 
by daylight;" and if so liable to decomposition, the repeated 
application of 212 F. was quite sufficient to resolve it into 
peroxide and metallic mercury, neither of which are acted on 
by acetic acid. 
But we have authority of much more weight, proving the 
presence of the protoxide of mercury as the active agent 
in this preparation. Eberle,* in the description of its pre- 
paration, says," the globules disappear, and the metal assumes 
the state of a black oxide," and Parist confirms it in the fol- 
lowing language: " The mercury in this'preparation is not, as 
it was formerly considered, in a state of mere mechanical di- 
vision, but in that of a black oxide, upon which its activity as 
♦Therapeutics, 1827. f Pharmacologia, vol. 2, 263. 
