The following paper contains the details of some experiments upon the action of ammonia on the oils and fats, of which a preliminary notice was published in the Quarterly Journal of the Chemical Society of London. The production of a soapy emulsion by the action of ammonia on these substances has long been familiar to chemists, but comparatively few accurate experiments have been made upon the compounds formed. Boullay long since examined the crystalline substance obtained from olive-oil, which he called Margaramide, and mentioned that similar compounds were obtained with the other oils, although he did not examine them. More lately, M. Bouis produced ricinolamide from castor-oil, and showed that, by fusion with potash, it yielded caprylic alcohol and sebacic acid; and still more recently, he has obtained another fatty amide, which he calls Isocetamide, by the action of ammonia on the fat of the purging nut of the West Indies.