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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.
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.
It consists of two layers, an outer fibrous and an inner cellular layer; the cells, which are called osteoblasts, are continuous with those lining the Haversian canals and the medullary cavity. The arrangement of the blood vessels determines to some extent the incidence of disease in bone.
On the other hand, the formation of new bone may be exaggerated, the osteoblasts being excited to abnormal activity by stimuli of different kinds: for example, the secretion of certain glandular organs, such as the pituitary and thyreoid; the diluted toxins of certain micro-organisms, such as the staphylococcus aureus and the spirochæte of syphilis; a condition of hyperæmia, such as that produced artificially by the application of a Bier's bandage or that which accompanies a chronic leg-ulcer.
Arranged, bound, indexed, all these at once become accessible and valuable. I will take the first instance which happens to suggest itself. How many who know all about osteoblasts and the experiments of Ollier, and all that has grown out of them, know where to go for a paper by the late Dr. A. L. Peirson of Salem, published in the year 1840, under the modest title, Remarks on Fractures?
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.
#Regeneration of Bone.# When bone has been lost or destroyed as a result of injury or disease, it is capable of being reproduced, the extent to which regeneration takes place varying under different conditions. 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.
Arranged, bound, indexed, all these at once become accessible and valuable. I will take the first instance which happens to suggest itself. How many who know all about osteoblasts and the experiments of Ollier, and all that has grown out of them, know where to go for a paper by the late Dr. A. L. Peirson of Salem, published in the year 1840, under the modest title, Remarks on Fractures?
We believe that it will avoid confusion in the study of the diseases of bone if the osteoblasts on the surface of the bone are still regarded as forming the deeper layer of the periosteum.
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