1. Blood containing high concentrations of siderocytes was transfused into four recipients with spleens and into two who lacked a spleen. In the circulation of recipients with spleens the siderin granules rapidly disappeared while the transfused red cells remained. In the recipients who had no spleen both the granules and the red cells remained.
2. It is concluded that the spleen is somehow able to bring about the removal of siderin inclusion bodies without destroying the red cells that contain them.