ALCOHOL AS A TEST FOR CROTON OIL. 
883 
volumes , while the alcohol measured only 7 5 volumes (or 10 volumes oil -f- 10 vo¬ 
lumes alcohol = 10*94 oil -j- 9 - 0G alcohol). In this case the croton oil hod 
taken up three-quarters of a volume of alcohol .” I)r. Pereira considers that 
these fluids exert a mutual solvent action on each other, similar to that of ether 
and water. This mutual action, however, he states, “ is not uniform, but varies 
with the samples of oil. At first,” he says, 11 1 was inclined to ascribe this varia¬ 
tion to differences of purity in the several samples of oil examined, but I am 
now convinced this is not the case, and that they depend on other circum¬ 
stances.” 
“ Experiment 6 .—One volume of dark-coloured English-expressed croton oil 
was mixed with one volume of alcohol, sp. gr. -796, by shaking, without any 
additional heat, a uniform transparent mixture was obtained ; and no sepa¬ 
ration took place on standing for several weeks.” Upon which Dr. Pereira 
naturally asks, “On what does this difference depend? Does it arise from 
differences in the qualities of the seeds pressed, or from differences in the mode 
of preparing the oil?” He then, after acknowledging himself, indebted to 
Mr. Redwood for his first information of these facts, quotes the test of the 
Edinburgh Pharmacopoeia, and adds, “ I have never been able to verify this 
statement ;’ 1 and then repeats the results of experiment 6 , and proceeds, “ Mr. 
Redwood has verified the same fact with various samples of genuine croton 
oil,” “ and he finds that no subsequent separation takes place unless the mix¬ 
ture be subjected to artificial cold;" “in that case, the oil is found to have 
slightly increased in bulk, and the alcohol to have suffered a corresponding 
diminution of volume. I presume, however, that the statement of the Edin¬ 
burgh ColDere is intended to apply to the amber-coloured East India croton 
oil,” and alludes to the results of experiment 2 . 
Dr. Pereira then mentions “ a very interesting and important fact,” that 
“ croton oil enables other fixed oils to dissolve in alcohol ',’ 1 and gives an illus¬ 
tration in “ Experiment 17.—Two volumes of English expressed croton oil, 
one volume of olive oil, and three volumes of alcohol, were mixed together. 
By shaking, a homogeneous mixture was obtained.” He then states that he 
considers “these various facts to be best explained by supposing that croton oil 
contains some principle which confers the power of dissolving in alcohol , and that 
this principle does not exist in all samples in the same proportional quantity, 
and hence their unequal solubility in alcohol.” If “ the quantity of this solvent 
principle in croton seeds increases the longer the seeds are kept, we should have a 
ready explanation of the greater solubility of croton oil expressed in England from 
seeds brought from India , and which are often musty, than of those oils ex¬ 
pressed in India from fresh seeds .” 
Such, then, was the extent of our knowledge on this subject in 1850. 
In January, 1864, the British Pharmacopoeia was published, and in the Ma¬ 
teria Medica, under the head of “ Oleum Croton is. The oil expressed from seeds 
in England,” we find as follows: “Test.—Agitated with its own volume of alco¬ 
hol, and gently heated, it forms a clear solution, from which about three-fourths of 
the oil separate on cooling.” This test has been severely criticized, and in rather 
strong terms , in the numbers of the Pharmaceutical Journal for February and 
April, 1864, vol. v. 2nd ser. pp. 363 and 485. In the first of these, in a paper 
entitled “ Explanatory and Critical Notes on the British Pharmacopoeia,” we 
read, “ This test is about true as regards East Indian croton oil , but it is trot 
true with English croton oil , which is wholly and readily soluble in alcohol , and 
the solution thus formed is permanent at ordinary temperatures.” In the se¬ 
cond, under Lecture II., “ On the Organic Materia Medica of the British 
Pharmacopoeia,” delivered before the Pharmaceutical Society of Great Britain, 
on the 23rd March, 1864, we read, “ this is a mistake, the framers of the Phar¬ 
macopoeia having given the test for East India croton oil instead of that for 
