In a series of experiments on the feeding of animals with sulphur compounds with reference to the formation of fat, Baumann and Kast found that several of the products caused sleep, and they investigated the whole series of sulphons. Disulphon itself they found inactive, and a large number of the simpler members of the group were found to be inactive because they were not broken up by the body. In those sulphons, however, with a large number of methyl or ethyl groups, they found marked oxidation in the body with a strong hypnotic action. Sulphonal (diethylsulphondi-methylmethane), trional (diethylsulphonmethylethylmethane), and tetronal (diethylsulphondiethylmethane) they found were the best of these, and they have been introduced into therapeutics with success.