Bone marrow Bone marrow Bone marrow is a semi-solid tissue which may be found within the spongy or cancellous portions of bones. In birds and mammals, bone marrow is the primary site of new blood cell production or hematopoiesis. It is composed of hematopoietic cells, marrow adipose tissue, and supportive stromal cells. In adult humans, bone marrow is primarily located in the ribs, vertebrae, sternum, and bones of the pelvis. On average, bone marrow constitutes 4% of the total body mass of humans; in an adult having 65 kilograms of mass (143 lb), bone marrow typically accounts for approximately . Human marrow
Annum sacrum Annum sacrum Annum sacrum (meaning Holy Year) is an encyclical by Pope Leo XIII on the consecration of the entire world to the Sacred Heart of Jesus. It was delivered in Saint Peter's Basilica in Rome on the 25th day of May, 1899, the twenty-second year of his pontificate. "Annum sacrum" was published on 25 May 1899, in anticipation of the Holy Year declared for 1900 to usher in the twentieth century. When the Church, in the days immediately succeeding her institution, was oppressed beneath the yoke of the Caesars, a young Emperor saw in the heavens across, which became