The production of a hereditarily obese strain of mice has been recently reported by Ingalls and associates.1 Whereas the weights of young adult normal mice are in the range of 16 to 26 gm., the young adult obese mice weigh 38 to 56 gm. A study of the nutritional and metabolic abnormalities of these obese animals is currently reported by Mayer2 and associates of Harvard University and Jackson Memorial Laboratory, Bar Harbor, Maine.
Ten obese and seven non-obese mice were placed in individual cages and given a free choice of three diets, each diet consisted of a mixture of fat, carbohydrate, and proteins fortified with minerals and vitamins. In one diet 90% of the total calory content was in the form of protein. The second diet contained 90% carbohydrates, the third 90% fats. They found that obese mice ate on an average five calories more per day than