Art. VI.—Sting-ray-liver Oil.
[Read before the Wellington Philosophical Society, 3rd December, 1919; received by Editor, 31st December, 1919; issued separately, 4th June, 1920.]
Mr. Hoyle, of Thames, conducted some experiments in the extraction of oil from sting-ray livers, and a quantity of about 8 oz., which he obtained from the liver of a single fish, was examined at the-Dominion Laboratory in September, 1918. The sting-ray was probably Dasybatis brevicaudatus (Hutton).
The oil was compared with cod-liver oil, with the following results:—
|Sting-ray-liver Oil.||Cod-liver Oil.|
|Specific gravity at 15.5° C.||0.927||0.923–0.930|
|Refractive index at 15° C.||1.4796||1.4800|
|Unsaponifiable matter (per cent.)||3.7||0.6–2.6|
|Hexabromides (per cent.)||45||42.9|
The oil was free from rancidity, and quite palatable. It contained some “stearine,” which made it cloudy at low temperature, and which, in the case of cod-oil, is usually removed by cooling and filtering.
If the present sample were similarly treated the product would scarcely be distinguishable in appearance or composition from good cod-liver oil.