666 
Rroceedings of the Royal Society 
3. On the Constitution of Adult Bone-Matrix and the 
Functions of Osteoblasts. By De Burgh Birch, M.B., 
Demonstrator of Physiology in the University of 
Edinburgh. 
{Abstract.) 
By tearing thin sheets from the surface of decalcified hones, 
Sharpey first demonstrated the lamellar nature of hone, and also 
that these lamellae have a fibrous structure. 
The fibres, consisting of two sets crossing each other, were thought 
to be interwoven in each lamella, and contiguous fibrous laminae to 
be separated from each other by a homogeneous ground substance 
in which the lime salts were mainly situated; alternations of 
fibrous and homogeneous layers giving rise to the appearance of 
lamellation. 
From the researches of V. Ebner and my own investigations, the 
matrix is undoubtedly throughout fibrous, the lamellar appearance 
being due to an alternation of layers in which the directions of the 
fibres differ. 
By digesting with trypsin sections of decalcified bone, the white 
fibrous tissue elements of which had been rendered indigestible by 
protracted treatment with chromic acid, the interfibrillar substance 
was entirely removed. 
In sections thus treated, an alternating band and dot series 
obtained, where one set of lamellae was cut longitudinally and the 
other transversely. 
In Haversian systems the entire system in section presented the 
same appearance, or the lamellation was perceptible only over 
certain parts, this difference being due to the fact that in some 
cases the fibres are arranged spirally, whilst in others they run 
parallel and transversely to the long axis. 
Trypsin digestion further caused the isolation of lacunar mem- 
branes with their tubular prolongations the canalicuh ; these were 
found united to similar membranes lining the interior of Haversian 
canals. 
Such membranes were also met with in the substance of the 
