PREPARATION OF MERCURIAL OINTMENT. 135 
But why is this state of alteration of the fatty matter 
favorable to the extinction of the metal ? The first thing 
that attracts our attention in rancid fat is its consistence. 
When it has been allowed to attain that degree of altera- 
tion at which it still possesses a certain softness, it will be 
perceived that it has acquired very marked agglutinative 
properties. When agitated in the mortar, it adheres strong- 
ly to the pestle. If a certain quantity of mercury is now 
poured into this triturated mass, and agitation continued, 
the metal is divided immediately, and the adhesion of the 
fat which surrounds each of the particles will necessarily 
prevent their reunion. 
I will now relate the facts which prove the truth of the 
above considerations. I had exposed for some months to a 
moist atmosphere about a pound of fat ; when I employed 
it, it was not hard, but it adhered strongly to the fingers. 
I took 200 grms., and triturated it for some minutes in a 
marble mortar, when it became soft like thick honey ; I 
then poured 4 lbs. of mercury in portions of 300 grammes, 
and five minutes of trituration always sufficed for the com- 
plete extinction of the metal. After the introduction of the 
fourth portion the ointment had become somewhat hard, 
but the addition of a little oil of sweet almonds allowed of 
the operation being easily continued. In this manner I was 
enabled to incorporate 4 lbs. of mercury in the 200 grms. 
of fatty substance. Not the least metallic particle could be 
detected with the lens throughout the whole mass. I then 
added the 1800 grms. of recent lard in a state of semifusion, 
and after a quarter of an hour's trituration I obtained a 
perfectly homogenous ointment, in which the mercury was 
extinguished most completely. 
N.B. The above process is not very new, but it is emi- 
nently successful. It is similar to the method of MM. Col- 
defy and Simonin, which consists in extinguishing the mer- 
cury in a small quantity of lard, which has been prepared 
by melting it, pouring it into water, and exposing it to the 
action of the atmosphere. — Journ. de Fharm. 
