ALCOHOL AS A TEST EOR CROTON OIL. 
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not but consider that a test which is open to so many weighty objections, both 
from the influence of small fluctuations of temperature, and for indicating the 
purity of a material liable to such marked differences from the effects of such 
natural and in some cases inevitable chemical changes, is perfectly useless as a 
reliable indication of purity. 
NOTE ON MR. WARINGTON’S PAPER, ENTITLED “ ON THE 
USE OF ALCOHOL AS A TEST FOR THE PURITY OF CRO¬ 
TON OIL.” 
BY PROFESSOR BENTLEY. 
In the above paper I am accused of having in the ‘Pharmaceutical Journal’ 
severely criticized in rather strong terms , the “test ” given in the ‘ British Phar¬ 
macopoeia,’ for “ English Croton Oil.” What the author means by severely 
criticized in rather strong terms , I am at a loss to conceive, as I simply stated 
the results which had been obtained by experiment (at least, in all their essen¬ 
tial particulars) by Pereira and Redwood, and which were commonly received 
by scientific men, and published in all works treating of Materia Medica up to 
the publication of the ‘British Pharmacopoeia,’ in January, 1864. 
The test given in the ‘ British Pharmacopoeia’ for “CrotonOil expressed from 
seeds in England” is, as follows :—“ Agitated with its own volume of alcohol, 
and gently heated, it forms a clear solution, from which about three-fourths of 
the oil separates on cooling.” In commenting upon this test, I stated in the 
numbers of the ‘Pharmaceutical Journal ’ for February and April last, that “This 
test is about true as regards East Indian croton oil, but it is not true with 
English croton oil, which is wholly and readily soluble in alcohol, and the so¬ 
lution thus formed is permanent at ordinary temperatures.” In remarking upon 
this criticism, Mr. Warington says, “I presume that these statements, from their 
general context, are derived from the results published by Dr. Pereira in 1850. 
But if it is so, how is it that they are not concordant with those results /” 
and he afterwards adds, “such statements should surely have been carefully ex¬ 
amined into before they were put into print.'' 1 Mr. Warington then quotes some 
experiments of Dr. Pereira’s which indicate, that when equal volumes of alcohol 
and East Indian croton oil are agitated with a gentle heat, the resulting mix¬ 
ture after being allowed to stand for two days, showed the oil had increased 
nearly one-tenth in volume. Now it is quite true that my remarks were 
founded, to a great extent, upon the results obtained by Dr. Pereira, but not 
wholly so, for during the last twelve years I have examined several specimens 
of East Indian croton oil, and have always found them to vary in their rela¬ 
tions to alcohol. Indeed, Dr. Pereira himself states in his ‘ Materia Medica ’ that 
“ according to Dr. Maclagan, only ninety-six per cent, of the oil separates. It is 
obvious, therefore, that commercial croton oils believed to be genuine, are not 
uniform in their relation to alcohol.” When such conflicting results are obtained 
from operating upon different specimens of East Indian croton oils, I can¬ 
not admit that I was much in error in the statement I made in the ‘ Phar¬ 
maceutical Journal,’ but, on the contrary, I believe that an extended series of 
experiments with ordinary commercial specimens of East Indian croton oil ex¬ 
amined without reference to age or temperature, will show that the term em¬ 
ployed “ about true ” is practically correct. I would further ask, is the bo¬ 
tanical source of all specimens of East Indian croton oils so absolutely certain as 
to enable us to say positively that they have all a common origin, and hence 
accordingly to be expected to yield similar results with alcohol ? 
But the question as regards the relations of East Indian croton oil to alcohol, 
