1. A method is described by which the relative water contents of adjacent microscopic regions of bone can be assessed. 2. The water content is correlated with the inorganic and organic contents in regions of different age. 3. The results suggest that the age increase in the mineralisation of bone occurs at the expense of both the organic and water fractions.
1. The relative concentrations of organic material in adjacent microscopic regions of bone have been studied by three methods, and the results suggest that this concentration varies considerably. 2. The variations in the organic concentration in bone have been correlated with the age of the bone and its inorganic concentration. 3. It is suggested that the progressive calcification of bone as its age increases, occurs, to some extent, at the expense of the organic fraction of the tissue.
1. The arrangement of collagen fibres in the secondary osteones in human femora and tibiae has been examined. The fibres were observed in paraffin sections stained by Weidenreich's method. 2. Three fibre patterns have been observed. They differ from one another in the relative numbers of longitudinal and circumferential fibres which they contain, and in the degree of lamellation which they exhibit. 3. The incidence of the three fibre patterns has been correlated with the relative ages of the regions of bone in which they occur. 4. The possibility of a correlation between variations in fibre pattern and certain recent microradiographic observations is discussed.
1. The normal anatomy of the intervertebral disc of immature rabbits is described. 2. An account is given of the changes that occur after an operative incision in the ventral part of the intervertebral discs of rabbits which allowed the escape of the nucleus pulposus. The account is based on observations made on fifty-five young animals killed at intervals during the twenty-five months after operation. 3. The superficial part of the wound in the annulus heals rapidly by active fibrosis. Thereafter there is a chondrification of the ventral region of the disc, followed by ossification. A prominent bony ridge ultimately ankyloses the vertebrae adjoining the disc. 4. The site of the nucleus pulposus is eventually occupied by a dense pad of fibrocartilage. A tongue of this tissue projects into the deep median part of the wound which remains unhealed. 5. A hypothesis is submitted regarding the mechanism of rupture of the annulus fibrosus and prolapse of the nucleus pulposus in man; this hypothesis is based in part on the observations of lesions in discs not subjected to operation.
