OIL OF RUE PROM COD-LIVER OIL. 
373 
procure the odoriferous substance in sufficient quantity for 
analysis, I mixed pretty considerable quantities of cod-liver 
oil and sulphuric acid, then saturated with potash or lime, 
and distilled with water. The water which passed over 
was turbid, and possessed an excessively strong odor of rue ; 
but only in a few cases was I able to perceive any drops of 
oil on its surface. Other experiments, in which I treated 
the fatty acids separated from the saponified cod-liver oil 
in a similar manner, furnished no better results. Fish oil 
and train oil from train-oil soap, submitted to a similar treat- 
ment furnished the same result. 
I am not able to state more of the oil obtained, than that 
it is of a light yellow color, lighter than water, boils about 
572°, and possesses the pure odor of the oil. With respect 
to the remarkable production of this oil from train oil by 
the action of sulphuric acid and subsequent saturation with 
a base, I may observe, that it certainly exists as such in the 
train oil, and cannot be considered as a product of decom- 
position by sulphuric, acid. I found amongst the volatile 
fatty acids of cod-liver oil butyric and capric acids. Now, 
if we bear in mind that Gerhardt has recently asserted that 
the oil of rue is the aldehyde of capric acid, C 20 H 20 2 , 
which he rendered probable by converting it by treatment 
with nitric acid into a different acid of the formula 
(C 2 H 2 ) n +40, pelargonic acid, we may be allowed to con- 
clude that the sulphuric acid enters into a combination with 
the aldehyde of capric acid, or rather with the oxide of 
caprinyle, C 20 H 19 0, and that this compound is decomposed 
on the addition of a base, when aldehyde separates. This 
aldehyde, on becoming rancid, that is by the absorption of 
2 equivs. oxygen, forms capric acid, C 20 H 19 O 3 -f HO. That 
the latter does not give rise to the production of the oil of 
rue is shown from the fact, that the capric acid is not at all 
altered by mixture with sulphuric acid. 
The characteristic odor of the oil of rue or of the aldehyde 
of capric acid furnishes us with the means of detecting the 
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