250 
MINUTE DIVISION OP MERCURY. 
solidified mercurial ointment by exposing it to a freezing 
temperature, or by saponifying it, I have seen the mercury 
separate in large globules by trituration, which also occurs on 
drying the mercury and gum {mercure gommeux) of Plenck, 
and the pills of Belloste, which I have verified several times." 
The effect which consistence has in favoring or obstruct- 
ing the division of mercury, throws some light on the 
increased facility which grease possesses when rancid, of 
effecting the disappearance of the globules, which circumstance 
was formerly supposed to depend upon the promotion of oxi- 
dation. In becoming rancid, the stearine and elaine in oint- 
ments become converted into margaric and oleic acids, and a 
substance is also generated resembling a volatile oil, in its 
viscous property. M. Desmarest has shown, in the paper 
above mentioned, that the peculiar viscosity which belongs to 
essential oils, is favorable to the extinction of the mercurial 
globules, and the consistence of rancid ointment being altered 
by the decomposition, we may infer that the difference of its 
effect on the metal is more mechanical than chemical. 
If the extinction were occasioned in all cases by chemical 
action, we might expect to find that sugar, which is unfavor- 
able to oxidation, would be incapable of effecting the change. 
To ascertain the limitations of the divisibility of mercury, by 
means of saccharine substances, the following experiments 
were tried. Two drachms of mercury were rubbed with 
simple syrup of the ordinary consistence, for above half an 
hour ; no change had taken place in the metal. The globules 
ran together as freely as ever, and appeared more obstinately 
metallic than before. Powdered sugar was added in small 
quantities, and the trituration was continued. When the 
syrup assumed a plastic viscous consistence, the mercury 
appeared unable to resist its influence, and gradually became 
divided without difficulty. In less than half an hour the 
globules were quite extinct, or at least they were invisible 
with the naked eye. Water being added, and the sugar dis- 
solved and separated, the residuum was a black precipitate, 
similar to that which results from treating hyd. cum creta 
