102 
PHARMACEUTICAL NOTICES. 
neatsfoot oil, why would it not be as easy, or preferable to 
use all lard, if, by so doing, the same intention is fulfilled? 
That it is so, I would wish the pharmaceutic public to judge 
from the following: 
Dr. Duncan, of Edinburg, states in his Dispensatory, that 
with lard alone he prepared an ointment which retained the 
required color and consistence. To this fact I would give ad- 
ditional strength, by stating that for four or five years past I 
have sought no other vehicle for making the ointment of ni- 
trate of mercury than butcher's lard. My method of proceed- 
ing is first to rJrepare my solution of proto-nitrate, without 
heat; then melt the lard over a common fire in a metallic ves- 
sel, and transfer it to one of porcelain, (ointment jar.) This 
being done, I pour gradually the solution into the heated 
grease, (140° F.,) and commence stirring the mixture, while 
hot, with a wooden spatula for about ten minutes, which has 
the effect of increasing the temperature of the mixture some 
20° or 30°, and causing the escape of hyponitric acid vapors. 
I then set it aside to cool. If the stirring be prolonged, a vio- 
lent effervescence takes place, which may cause the mixture 
to overflow — and likewise renders it darker in color. 
Citrine ointment prepared in the manner here mentioned, 
diners from the one made with olive oil and lard, in being of 
an orange, instead of a lemon yellow color. It is of good con- 
sistence, perfectly homogenous, and retains these characters 
through summer and winter, without acquiring the mottled 
appearance of the other. 
Hypo-Sulphite of Soda. 
This is a chemical agent of some importance to those prac- 
tising the Daguerreotype art, being used in the form of a 
weak solution to wash off the superfluous iodine from the 
plate, after the object is depicted upon it. It is made by dis- 
solving two pounds of subcarb. sodse in three and a half pounds 
of water, into which is thrown four ounces of flowers of sul- 
phur, stirred in six ounces of water. A current of sulphurous 
acid gas, obtained from the decomposition of ten pounds of 
