256 



BIOLOGICAL PHYSICS 



foetus, by neuro-muscular plasma, provided from the 

 central, or systemic, nervous system, through the axonal 

 processes of its various neurons, which seem to repeat, on 



''""' :/i 



FIG. 107. IDEAL PLAN OF THE MULTIPLICATION OF CELLS OF 

 CARTILAGE. (Sharpey. ) 



A, cell in its capsule ; B, divided into two, each with a capsule ; C, primary capsule 

 disappeared, secondary capsules coherent with matrix ; D, tertiary division ; E, 

 secondary capsules disappeared, tertiary coherent with matrix. 



the same lines, the ossificatory proceedings of the early 

 notochord, each neuron carrying, or sending, to its appro- 

 priate osseous centre of attachment and distribution, the 



FIG. 108. DIVISION OF A CARTILAGE CELL. (Schleicher.) 



a-/t, stages of division of a cell, as seen in the living cartilage of the salamander (the 

 connection of the nucleoplasmic filaments could not be made out in the fresh con- 

 dition), a, 6, stellate phase ; c, equatorial phase ; d, commencing separation of 

 the nucleoplasmic filaments; the further stages of separation are not represented ; 

 e, filaments fully separated into two groups, and a septum beginning to be formed 

 between them ; f, septum completed, seen to be double and continuous with cap- 

 sules of daughter cells ; , h, further stages in the formation of the daughter nuclei. 



requisite plasmic and earthy material, for the solidification, 

 and ossification, of the point, or area, to which it is 

 locally conveyed. Ossification is said to manifest itself in 

 two ways, or manners, viz. by (Figs. 107, 108) cartilage, 



