In studies which require an accurate detn. of food intake the spilling of food and its contamination by excreta must be kept to a minimum. Mice are notorious for their perversity in these respects. A special feeder consisting of 2 easily assembled parts which has given very satisfactory service is described. The feeder as described may be used for groups of 2 to 24 young adult mice but can also be constructed of proper sizes to accommodate rats of varyingsize. A detailed diagram of the feeder accompanies the article.