With the purpose to elucidate morphologically the site where fat synthesis takes place in the cell, electron-microscopic observation has been conducted on the interscapular brown fat tissue of mice at various periods of carbohydrate introduction after starvation. By starving mice, the depot lipids in the brown fat have been discharged almost completely, and the carbohydrate introduction has caused the biosynthesis of lipids from carbohydrtates in the same tissue. Observations on the tissues proved that the lipogenesis in the brown fat tissue cells takes place in the ground substance keeping the intimate correlation with the endoplasmic reticulum but not in the mitochondria.</p
