The revival of the use of cod liver oil in therapeutics and the newly awakened interest concerning its action have stimulated this inquiry into the history of its employment in medicine. The use of fish oils in medicine is mentioned by Hippocrates,1 and Pliny2 writes that the oil of the livers of the dolphin was used for chronic eruptions of the skin, not only as an external application, but also internally. No definite mention of the oil from the various species of Gadus is found in Greek and Roman literature (Bennett). Apparently, however, cod liver oil has been used by the fisherman along the coasts of northern Europe for many years. It is stated that, in the Island of Shetland and the north of Scotland generally, the liver of the cod has long been considered a special delicacy, and hence is given to invalids and people in poor