Cod Liver Oil is a remedy of great antiquity and is said to
have been used by the Greenlanders, Laplanders and Esquimaux before they came in touch with civilisation.
The oil used by these primitive peoples was doubtless a
very crude product and various improvements in the preparation
of the oil have been made since these early days.
The oil is extracted from the Livers of the various Gadidoe.
No practical difference exists in the Morphology of the Liv
ers of the various Gadidoe, although differences exist in the
oil expressed from the Livers of fish in the various fisheries,
probably due to care in selection of thé cod rejection of other
species and to the special environments of each fishery, i.e.
Temperature, Depth. of water, and Food supply &c. This can
seen in the differences between Norwegian and Newfoundland Cod
Liver Oil.
The yield of oil from the Livers also varies greatly in
different years according to modifications of Temperature and
food supply.
Three varieties of medicinal oil are recognised in commerce
pale. light brown and brown; but these insensibly merge into
each other, and are only the result of different processes or
periods of preparation, as mentioned above. The pale oil possesses a fishy odour and a slight acrid taste, while with the
darker oil there is a distinctly disagreeable empyretunatic odour
and taste. In composition the oil contains olein and margarin
with small proportions of free butyric and acetic acids, a peculiar principle termed gaduin, certain bile acids, free phosphorus, phosphatic salts, and traces of iodine and bromine. Cod
liver oil is valuable in medicine on account of its great nutrient properties; it aids rapidly to the store of fat within
the human frame, and it enriches the blood in red corpuscles.
It is much more digestible than other animal oils, a fact which
may account for its superior therapeutic value. At one time
it was supposed that its virtues resided in the iodine and bromine which the oil generally contains; but these are present in
only exceedingly minute proportions, and sometimes they cannot
he traced at all. The oil has long been favourably known in
medicine as a remedy for rheumatic complaints, but its great
value in pulmonary consumption has been demonstrated only in
comparatively recent times. It is administered internally in
chronic rheumatism, scrofula, phthsis, chronic skin diseases,and
general debility; and it is sometimes externally applied in affections of the skin. The oil is taken with facility by young
children; but the repugnance of adults to its taste and eructations is not easily overcome,and many methods have been suggested for masking its taste. With that view the oil is enclosed in
gelatinous capsules, or prepared in the form of aromatised emulsions of equal parts of mucilage, of gum tragacanth and the oil.
There are numerous other forms of emulsions recommended, as well
as combinations with medicinal syrups, and cod liver creams,jellies and bread; and various devices are familiarly employed as
in the administration of unpleasant medicines. Failing all
these, cod liver oil has been introduced into the system by
injection.
