138 
ON COD-LIVER OIL. 
jecoris gadi, or cod-liver oil,\ is indiscriminately applied, 
though it is commonly used, especially in this country, to 
indicate the oil procured from the liver of the common 
cod, {Gadus m or r hua, Cuv.) It would be better, there- 
fore, to employ the term oleum jecoris morrhuse, or simply 
oleum morrhuse, when it is intended exclusively to desig- 
nate the latter oil. 
De Jongh, in his " Disquisitio comparativa chemico- 
medica de tribus olei jecoris aselli speciebus," published at 
Leyden, in 1843, states that the Bergen (Norwegian) oil is 
principally obtained from three species, viz. the dorse (Gadus 
callarias,) the coal-fish (Gadus ^carbonarius,) and the pol- 
lack (Gadus pollachius,) but chiefly from the first. 
In general, continental writers distinguish three varieties 
of cod-liver oil, one white or pale yellow, a second brownish- 
yellow, a third dark-brown. But between the finest pale 
yellow or almost colourless oil, and the dark brown cod- 
oil used by curriers, there is an almost infinite variety of 
shades, so that no absolute difference can be founded on 
colour only. 
De Jongh made, in Mulder's laboratory, a very elaborate 
former. Varro {Opera Omnia, p. 21, Durdrechti, 1619) says that 
these fishes derived their name aselli. from their resemblance in colour 
to the ass. 
By some later writers, the term asellus has been extended to 
several species of the cod tribe. Thus, the common cod is called 
asellus major ; the ling, asellus longus ; the coal-fish, asellus niger; the 
whiting, asellus albus ; the dorse, asellus striatus ; the pollock, asellus 
haifingo, &c. 
A few years ago, a writer in one of the medical journals, mis- 
taking the meaning of the word asellus, graveJy announced, that u oil 
of the liver of the ass" had been introduced, as a remedial agent, into 
Germany, from Sweden ! 
* The term cod-liver oil is here used to indicate the oil obtained 
from the livers of any of the cod-tribe. In this sense it is about 
equivalent to the Latin term oleum jecoris aselli. 
