142 
ON COD-LIVER OIL. 
insoluble in water, alcohol, ether and diluted sulphuric acid, 
but by concentrated sulphuric and hydrochloric acid is con- 
verted into a black powder, without freely dissolving; in 
hot nitric acid it gradually and completely dissolves. It 
dissolves in alkalies, forming a red-coloured solution. In 
burning, it evolves the odour of acetic acid, and leaves 
about 0.822 per cent, of ashes. When dried at 23S° Fahr. 
its composition is C 39 H 26 O l2 =-C 35 II 22 8 f . + C 4 H s O s + HO: 
that is gaduin (C 35 H 22 O 8 , HO) combined with acetic acid 
(C 4 H 3 H 3 .) But De Jongh's formula scarcely agrees with 
his experimental result. He says that analysis gave him 
7.04 per cent, of hydrogen, whereas his formula indicates 
about 7.3 per cent. 
Berzelius states that when he read De Jongh's account 
of gaduin, he was struck with the analogy of the reactions 
of this substance with those of bilifulvic acid, and he tells 
us that he was disposed to think that gaduin is primitive 
bilifulvic acid, and that the reddish-brown substance, inso- 
luble both in alcohol and water, which he (Berzelius) sepa- 
rated from bilifulvin by long and numerous operations, is 
only the insoluble modification of gaduin. This point, 
however, at present remains undetermined. 
Gaduin is contained in all the three varieties of oil ex- 
amined by De Jongh. At first it is yellow, but under the 
influence of atmospheric air it acquires a brown colour. 
2, Fatty acids ; margaric and oleic acids. — These acids, 
as obtained from cod-liver oil, do not appear to differ in 
their nature and composition from the same acids procured 
from other sources. De Jongh analysed them in the form 
of margarate and oleate of lead. The results were as fol- 
lows : 
Margarate of lead - - C 34 H 33 O 3 PbO. 
Oleate of lead - - - C 44 H 39 O 4 PbO. 
3. Glycerin— This was obtained by saponifying cod- 
liver oil by caustic soda. The residual lye was decanted 
from the soda-soap, saturated with sulphuric acid, and the 
