REMARKS ON COD LIVER OIL. 
103 
and by standing on the acid it gets darker, and finally is slowly 
decomposed, frothing over with evolution of nitrous gas. 
Nitric acid of sp. grav. 1.215, (formed by mixing 3 parts of ordi- 
nary white nitric acid with 2 parts of water), when shaken with it, 
at first produces no change, but gradually the oil assumes a dull 
green hue, retaining its transparency. After standing four days on 
the acid, the green color slowly changes to brown. Mixed with 
an acid solution of nitrate of mercury (as used for citrine ointment), 
the oil thickens, becomes yellow, and finally orange-yellow, with 
evolution of nitrous gas and much frothing. - 
The specimen of haddock liver oil has less color than the cod oil, 
has a slight lamp oil odor and taste, and its specific gravity is. 9 195. 
It reacts with sulphuric acid, acid nitrate of mercury, and nitric 
acid sp. gr. 1,36, almost precisely like the cod oil. Nitric acid 
sp. gr. 1 .215 after contact for four days colors it a clear brown with- 
out a shade of green. 
The specimen of hake liver oil resembles the haddock oil in co- 
lor, odor and taste, Its specific gravity is .915. It reacts with sul- 
phuric acid, nitric sp. gr. 1,36, and the acid nitrate of mercury in 
the same way, but with nitric acid sp. grav. 1.215; by standing 24 
hours it gradually assumes a greenish brown color, which it loses as 
the action of the acid continues, and becomes of a light brown hue, 
much lighter than that of the haddock oil. 
The specimen of pollack liver oil very closely resembles the 
hake oil in color, odor, and taste, and in all the reactions with 
sulphuric and nitric acid. Its specific gravityis .9155. 
Sperm (lamp) oil, when treated with nitric acid sp. gravity 1.36, 
is colored pinkish brown gradually, but when a itated with the 
acid sp. grav. 1.215, it assumes only a pale brown color without a 
shade of green, hence the presence of this oil or of haddock oil 
should render the green color occasioned by this acid on true cod 
oil to be less deep. 
These reactions are not offered as affording reliable means of 
distinguishing true cod-liver oil, either from the liver oil of allied 
species of fish, or from whale oil. To arrive at any such desirable 
criteria we must be better acquainted with the organic constituents 
of all the oils, and their relations to reagents. Yet they may 
serve to show how little dependence can be placed in the action 
of the so called tests for cod-liver oil, sulphuric and nitric acid. 
