377 
upon Dr. James's Powder. 
which resists the action even of nitro-muriatic acid, it is not my 
purpose to determine. It is sufficient for me to say, that, as the 
quantity of insoluble matter, in a given quantity of Dr. James's 
Powder, prepared at different times, may vary, the effect of any 
dose also may differ, according to the proportions of soluble 
and insoluble matter. 
I look upon it as a fortunate circumstance, that those experi- 
ments and observations which I mentioned in the beginning of 
this Paper, existed as a standard to which I might refer my own 
attempts, and by which I might estimate their validity. Dr. 
Pearson has proved, (as by my own experiments I have found,) 
that in Dr. James's Powder about 28 per cent, resisted the 
action of every acid. In examining some of the Pulvis Antimo- 
nialis of the London Pharmacopeia, I found the average quantity 
of insoluble matter to be about 44 per cent. This proportion, 
however, was liable to considerable variation.* 
The powder here treated of is denominated, by Dr. Pearson, 
a triple salt, or a real ternary combination of a double basis, 
(lime and antimony,) faith phosphoric acid. What I have men- 
tioned, with regard to the quantity of acid contained in bone or 
hartshorn, as being too small to saturate a new portion of these 
bases, may throw some doubts upon the possibility of any such 
combination in the present case. But I have made some more 
direct experiments, which tend to prove, that no such combina- 
tion does exist. 
* I find, from the information of several medical gentlemen, that the Pulvis Antimo * 
malishs generally considered as stronger than Dr. James’s Powder. This seems rather 
extraordinary, when we consider that the quantity of insoluble matter is greater in the 
former than in the latter; and would almost lead us to suspect it to be the active part 
of the medicine. 
3C 
MDCCCI. 
