PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 263 
portion separated by filtration at 60° remains bright at all temper- 
atures above that point, and has a very slight yellowish tint, resembling 
that of the best pale cod-liver oil. When a few drops of sulphuric acid 
are added to a small quantity of the oil, placed in a porcelain capsule, it 
assumes a deep brown tint, without in the first instance affording the 
- violet color which is produced under similar circumstances by cod-liver 
oil. If, however, the mixture thus formed be allowed to remain exposed 
to the air for several hours the violet color becomes developed. If an 
ounce or two of the Eulachon oil be boiled with about twice its volume 
of distilled water, and the water after being carefully separated and fil- 
tered be evaporated to dryness, a small quantity of a brown extractive 
matter will be left, which closely resembles the extract obtained under 
similar circumstances from cod-liver oil. 
_ The Eulachon oil readily saponifies with caustic alkali, and the soap, 
after being decomposed with acetate of lead, yields oleate of lead to 
ether, but the oleic acid resulting from the decomposition of this is not 
brown like that obtained from cod-liver oil. 
‘“‘Eulachon oil, therefore, although in some respects resembling cod- 
liver oil, differs from it in some of its chemical and physical characters. 
The resemblance to cod-liver oil is, however, greater than that of any 
other oil Iam acquainted with that is not extracted from a fish liver. 
“THEOPH. REDWOOD.” 
It would have been interesting if Professor Redwood had given the 
exact analysis of Eulachon oil, as that of the cod liver has been fully 
given in various medical works. The student of medicine could have 
thus been able to have compared the twe together, and have found what 
constitutes their medicinal value. 
Professor Redwood says that the oleic acid resulting from the decom- 
position is not brown like that of the cod-liver oil. The brown color is 
owing to the presence of a peculiar substance obtained by an analysis 
of cod-liver oil by De Jough, and named by him gaduin, but it has not 
been ascertained that gaduin is in any way connected with the virtues 
of the oil. 
It has been thought that the action of the liver carbonizes the oil ina 
manner and thus renders it more susceptible of being taken up and as- 
similated by the systems of persons to whom it is administered. It is 
not improbable that the biliary principles associated with the oil are 
concerned in its peculiar influences. Winckler has inferred from his re- 
searches that cod-liver oil is an organic whole, differing from all other 
fixed oils. Eulachon oil, although a body oil, instead of a product of 
the liver, seems to possess properties essentially different from all other 
fish-oils, and future analysis may show that the curative principle of 
cod-liver oil does not lay in any of the causes mentioned, but in some 
hitherto undeveloped principle, which is identical with that of the Eu- 
lachon. I find no mention of the Eulachon in the voyages of Portlock, 
