COD-LIVER OIL. 
649 
bination—perhaps, as an iodic fatty acid. De Jongli determined 
the proportion of iodine by forming iodide of palladium; every 100 
parts of anhydrous iodide of palladium was considered equivalent 
to 70.34 parts of free iodine. 
The largest amount of iodine found in genuine oil is less than 
0.05 per cent. If the amount obtained be larger than this, fraud 
may be suspected. It is said by Dr Martiny* that some dishonest 
druggists have introduced iodine into the oil for the purpose of 
augmenting its commercial value. Nay, it is stated that an artifi¬ 
cial cod-liver oil has been made by combining iodine with common 
fish or train oils. 
De Jongh detected bromine in the oil by Balard’s process. The 
carbonized soap was digested with alcohol, and the alcholic extract 
treated with chlorine gas and ether. Its proportion was estimated 
in conjunction with that of chlorine, as the quantity was too small 
to admit of accurate separation. 
The chlorine was determined by precipitating it as chloride of 
silver from the watery extract of the carbonized soap. 
6. Phosphoric and sulphuric acids .— Phosphorus. —Dr. Jongh 
determined the presence and quantity of these ingredients in the 
following way: The oil was saponified by potash, and the soap 
thus obtained decomposed by hydrochloric acid, by which the fatty 
acids were separated. From the solution the phosphoric acid was 
precipitated by a nitrate of iron (whose proportions of oxide was 
known) and ammonia, and the sulphuric acid by means of nitrate 
of baryta. 
In order to determine the presence and quantity of free phos¬ 
phorus or sulphur, a given quantity of oil was decomposed by con¬ 
centrated nitric acid, and the quantity of phosphoric and sulphuric 
acids in the oxidized liquid ascertained by the above-mentioned 
method. More phosphoric acid was procured from the oxidized 
than from the unoxidized liquid, and the proportion of phosphorus 
was calculated from the excess of acid. 
7. Acetic and butyric acids. —De Jongh separated these volatile 
acids from cod-liver oil by adding sulphuric acid to the soda-soap, 
and distilling the liquid thus obtained. The distilled product had 
a peculiar odour. It was saturated with barytic water, and eva¬ 
porated to dryness. One portion of the residue was insoluble in 
alcohol, the other was soluble. The insoluble salt was acetate of 
baryta with two equivalents of water (=C 4 H 5 0 5 , BaO); the 
soluble salt was butyrate of baryta. The soluble salt obtained 
* Naturgeschichte der fur die Heilkunde wichtigen Thiere. Darmstadt, 
1847. 
VOL. XXII. 4 R 
