52 REMARKS ON SOME OP THE MERCURIAL COMPOUNDS. 
a remedy undoubtedly depends; for mercury in its metallic 
state is entirely inert with regard to the living system." 
In a series of experiments in relation to this subject, Mr. 
Donovan* has satisfactorily proved that one hundred grains, 
or parts of mercury, after being rubbed or triturated for forty 
hours with honey, yielded ten per cent, of protoxide of mer- 
cury, and "its introduction as a substitute for those prepara- 
tions in which the metal is oxidated by friction, is supposed 
to be advantageous from the uniformity of strength, as the 
others are liable to vary from imperfect preparation; when 
properly prepared, it appears to be the same in chemical com- 
position, and the medicinal operation of it also extremely si- 
milar."! 
These experiments of Mr. Donovan have long since de- 
cidedly settled this question in Europe, with the exception of 
some of the French writers, who are generally loth to adopt 
ideas promulgated by their English cotemporaries, but the 
opinion of Dr. Thompson^: on the subject is at least entitled to 
respect, as proof of the importance which deservedly is at- 
tached to them. To counteract the effect of at least some of 
the essays which have been written on this subject, I have re- 
cently examined samples of the several varieties of blue mass 
which are found in our drug stores, and with the following re- 
sults. Repeated washings by water, at common tempera- 
ture, was used at first to remove the feculous and saccharine 
matter, after which the residue was digested with pure acetic 
acid diluted, which, being slowly evaporated, yielded flaky 
crystals of acetate of mercury. 
Hydrochloric acid was then substituted for the acetic, eva- 
porated, and the white residuum was rendered black by the 
addition of potassa, ammonia and hydrosulphuric acid, prov- 
* Annals of Philosophy, vol. 14. f Murray. 
X " Every chemical reader who peruses the paper will agree with me 
in thinking, that it possesses unquestionable merit, and that Mr. Donovan- 
has added very materially to the accuracy of our knowledge of the com- 
pounds of mercury," &c. Thompson's Annals, vol, 16, page 17. 
