Osteoporosis and the Replacement of Cell Populations of the Marrow by Adipose Tissue

*Laboratoire de Recherches sur l'Histodynamique Osseuse, Chaire d'Hydrologie Therepeutique, Faculte de Medecine, 8 Av. Rockfeller, 69. Lyon (8e), France. †Reaserch Assistant, Mineral Metabolism Unit (Dr. B.E.C. Nordin), General Infirmary, Leeds 1, England.