COMPOSITION. Besides a large proportion of fats, cod-liver oil has been shown to contain (1) a peculiar principle called giluii6 (C.H450,0 ; (2) a crystalline substance called myrrh col ( 3) traces of bromine and iodine: ( t) bh hngy prin eiples: and other substances. The brown oils contain also considerable quantities of ptomaines, which cannot but be injurious to health; bleach ing brown oil by sunlight only masks the pres ence of such substances without destroying their injurious properties, and should therefore not be resorted to. it is generally believed that the great benefit derived from cod-liver oil in tuber enlosis is due to the specific aelion of some active principle that must he contained in the oil. It is probable. however, that the effect is due to nothing but the food-value of the fatty constituents of the oil. These fats are commonly assumed to consist, like other natural fats, of the glycerides of oleic, palmitie, and stearie acids. Miller's chemist. P. M. Ileyerdahl, states,
on the contrary, that cod-liver oil contains a little pahnitic, but no oleic or stearic acid: ac cording to him it consists mainly of the glyeer ides of therapie and *oleic acids (C„14,0, and Ca.11,,8U_, respectively), two unsaturated organic acids which are not known to exist anywhere else in nature, and to which the therapeutic action of cod-liver oil is due. The solid fat that is some times removed by freezing the oil is, according to Ileyerdahl, also composed mainly of those glycerides; so that its removal appears to serve no purpose whatever. In view of the readiness with which the fats of cod-liver oil undergo oxidation, the oil should be kept out of contact with the air. Cod-liver oil is now prepared in Norway. the United States, Canada, Newfound land, tIreat Britain, Iceland, and Russia. By far the greater proportion of the oil reaching the market comes from Lofoten and Romsdal in Norway.