ON THE COMPOSITION OF JAMEs' POWDER. 159 
phosphate of lime in the form of a triple salt, in which state 
it escapes the action of the fire? There seems to be no rea- 
son to suppose that the antimonious acid in James' powder 
is chemically combined with the phosphate of lime, as was 
believed by Dr. Pearson, but merely that it is mechanically 
mixed with it. 
If this account of the composition of James' powder should 
be found correct, it will, I think, afford a sufficient explana- 
tion of the uncertainty of this medicine, and of the very dif- 
ferent estimation in which it is held by practitioners. What- 
ever virtues it possesses are probably due to the sesquioxide 
which it contains, and this we have seen to be the most 
variable of its ingredients. From the similarity of their com- 
position, it seems probable that both James' powder and the 
pulvis antimonialis are prepared in the same way. The 
patent medicine seems, however, to have been found to suc- 
ceed oftener than the preparation of the Pharmacopoeia, which 
may be owing to its being in general richer in sesquioxide 
from being more carefully exposed to the fire. I regret that 
I have not had time to compare a greater number of speci- 
mens of each, in order to see whether or not this is the 
case. 
There does not, however, seem to be any thing in the com- 
position or superior efficacy of James' powder, to justify the 
enormous price at which it is sold. Bottles which contain 
one ounce are charged at the extravagant rate of 1 1. 4s., whilst 
as much, pulvis antimonialis, perhaps little inferior in value, 
may be had at any laboratory for 6d. or 8d. 
Edinburgh Med. and Surg. Journ. April, 1S3S, 
