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ON LEAD PLASTER. 
There is, then, a real advantage in not washing the plas- 
ter, and in consequence in not kneading it. 
It should be, while hot, run into wooden moulds to cool 
slowly, by which any uncombined litharge may precipitate, 
and the excess of water rise to the surface. 
Thus prepared, the plaster may be spread without any 
other addition except of olive oil, when the weather changes 
from hot to cold, in which case the addition should be made 
before and not after melting the plaster. Heated together, the 
union is more intimate. It is an incontestable fact that fatty 
matter in the plaster, but not combined, favors rancidity, and 
it may be supposed that it is this rancidity that gives irritat- 
ing properties to the plaster when spread. 
Ceruse, which is sometimes added, if not hurtful, is at 
least useless : it is not of consequence that the whiteness 
of the plaster be more or less striking, provided it answers 
the purposed for which it is used. 
The practical observations which precede, have the sanc- 
tion of experience, as more than one pharmaceutist at 
Lyons has adopted and recognized the utility of the process. 
I believe we may draw the following conclusions : — 
1. Simple plaster may be prepared with less water than 
is usually employed. 
2. This plaster is the more supple, adhesive, and shining, 
as there remains less water interposed. 
3. Glycerine aids to maintain the plastic state, which 
renders useless the addition of oil, to prevent cracking. 
4. Washing and kneading are injurious : the one dissolv- 
ing and separating the glycerine, the other interposing air 
and water, which disposes the plaster to become rancid. 
5. Finally, if cold weather should necessitate the addition 
of oil, this should be added before liquefaction. 
Journ. de Chim. Med. 
