Crossword-Solution: OSTEOBLASTS 11 letters, 1 clue 🏆 scrabble score: 13

Rossiter in this autumn of 1917 was extremely interested in certain crucial experiments he was making with spiculum in sponge-cells; with scleroblasts, "mason-cells," osteoblasts, and "consciousness" in bone-cells.

His experimental observations appear to show that new bone is exclusively formed by the cellular elements or osteoblasts: these are found on the surface of the bone, lining the Haversian canals and in the marrow.

The formation of new bone by the osteoblasts may be _defective_ as a result of physiological conditions, such as old age and disease of a part, and defective formation is often associated with atrophy, or more strictly speaking, absorption, of the existing bone, as is well seen in the edentulous jaw and in the neck of the femur of a person advanced in years.

The chief part in the regeneration of bone is played by the osteoblasts in the adjacent marrow and in the deeper layer of the periosteum.

Investing bones were actual integumentary ossifications which had gradually sunk beneath the skin to become part of the internal skeleton; substitutionary bones were produced by cells (osteoblasts) which were ultimately derived from the integument.[460] A further instance of the historical interpretation of animal structure, taken from quite a different field, is afforded by the speculations of Dollo[461] on the ancestral history of the Marsupials.