296 Notice of new Medical Preparations. 
than white sugar. The seeds of the Palma Christi contain né doubt 
two oils, one bland and the other acrid, and in proportion as they 
are united by the difference in the process of manufacture, is this 
oil increased or diminished in activity; thus the cold expressed 
is more bland and less active than the hot pressed. The acrid 
oil resides in the skin of the beans and is obtained in greater 
proportion in the latter. If the oil were obtained from the skins 
alone, it would no doubt be as active as the croton, for if we swallow 
one or two of the beans, with the skins, the action is very powerful. 
I would by no means infer that in all cases of the combination of 
vegetable proximate principles such effects would result; we know, 
indeed, some instances to the contrary ; but in the cases above re- 
ferred to, there will probably be no diversity of opinion. 
In relation to the precipitated extract of bark, I must further state, 
that I have endeavored to have it tried as extensively as possible, and 
the result has been most satisfactory ; by many physicians it is pre- 
ferred to the quinine, and they will probably use the latter rarely, 
when they can obtain this extract at so low a price. - 
1 would wish it to be particularly understood, that this is not the same * 
as that formerly sold under the name of extract of quinine, as it con- 
tains all the essential properties of the bark and is destitute of no princi- 
ple except gummy matter, gluten and the woody fibre, which are inert. 
2. Oleo-Resinous Extract of Mustard or Oil of Sinapine. 
The seeds of the Sinapis nigra have been found, by long experi- 
ence, to be one of the most useful of all the rubefacients. It is usu- 
ally applied, as is well known, in the form of a paste, made with the 
farina of the seeds and vinegar, which is to be applied in the manner 
of a poultice. This is frequently attended with considerable difficul- 
ties and inconveniences; and mustard differs so essentially in quality, 
that little dependence can be placed upon the certainty of its effect. 
Ii is, almost always, more or less adulterated, and the flour which is 
sold from the stores is frequently composed of more than half for- 
eign or inert matter. At the suggestion of our distinguished profes- 
sor, Dr. Physick, I have made a series of successful experiments on 
the mustard, with a view of ascertaining the active constituent prin- 
Ciple, and separating it, in a form best adapted for its application as @ 
jent. I have obtained, separately, the active principle of the 
mustard, which is combined with a volatile acrid oil.* 
» A Voll nailed oF ike aay : as 
the Materia Me stead eg in the second edition of my Essays on 
