At a time when the value and necessity of fats in foods are recognized as never before, the determination of the digestibility of those from new or little used, although abundant, sources is both interesting and important. Of as great interest is the comparison of their utilization with that of the fats for which they can be substituted. In this country a potentially rich source of edible oil is the germ of maize or Indian corn, which is separated from the rest of the kernel in the starch-making process. Maize oil, or corn oil, has within the last few years been put on the market in increasing quantities. It is sometimes sold under these names, sometimes under trade names1that do not clearly indicate its source. The results of experiments here reported show the digestibility by dogs of corn oil compared with that of lard and cottonseed oil, for