Test for the Presence of Mercury.—If a strong solution of iodide
of potassium be added to a minute portion of any of the salts of mer-
cury, placed on a sheet of bright copper, a white metallic silvery stain
will be developed, which cannot be mistaken, as no other metal pre-
senting a similar appearance is deposited by the same means. In this
way corrosive sublimate may be detected, in a solution unaffected by
potash or iodide of potassium. In a mixture of calomel and sugar, in
the proportion of one of the former to two hundred of the latter, a dis-
tinct metallic stain will be detected with one grain of this mixture,
containing but l-200th of its weight of calomel; and the binoxide of
mercury can be thus detected, if mixed with 400 times its weight of
sugar. This valuable test we owe to Mr. Arthur Morgan.—Annals of
Pharmacy, from London Journal of Medicine,