The introduction of hardened oils has opened a new source of raw material for the soap manufacturer in that it is now possible to use oils in soap making which were formerly discarded because of their undesirable odors. Thus fish or train oils which had up to the time of oil hydrogenating resisted all attempts of being permanently deodorized, can now be employed very satisfactorily for soap manufacture. A Japanese chemist, Tsujimoto[3] has shown that fish oils contain an unsaturated acid of the composition C_{18}H_{28}O_{2}, for which he proposed the name clupanodonic acid. By the catalytic hardening of train oils this acid passes to stearic acid and the problem of deodorizing these oils is solved.[4] At first the introduction of hardened oils for soap manufacture met with numerous objections, due to the continual failures of obtaining a satisfactory product by the use of same. Various attempts have now shown that these oils, particularly hardened train oils, produce extraordinarily useful materials for soap making. These replace expensive tallow and other high melting oils. It is of course impossible to employ hardened oils alone, as a soap so hard would thus be obtained that it would be difficultly soluble in water and possess very little lathering quality. By the addition of 20-25% of tallow oil or some other oil forming a soft soap a very suitable soap for household use may be obtained. Ribot[5] discusses this matter fully. Hardened oils readily saponify, may be perfumed without any objections and do not impart any fishy odor to an article washed with same. Meyerheim[6] states that through the use of hydrogenated oils the hardness of soap is extraordinarily raised, so that soap made from hardened cottonseed oil is twelve times as hard as the soap made from ordinary cottonseed oil. This soap is also said to no longer spot yellow upon aging, and as a consequence of its hardness, is able to contain a considerably higher content of rosin through which lathering power and odor may be improved. Hardened oils can easily be used for toilet soap bases, provided they are not added in too great a percentage. The use of hardened oils is not yet general, but there is little doubt that the introduction of this process goes a long way toward solving the problem of cheaper soap material for the soap making industry. GREASE.