482 



MOVEMENTS. 



of preparation of the thin sections of bone. They are con- 

 nected with numerous little canals, giving them a stellate 

 appearance. These are most numerous at the sides. The 

 lacunae measure from y^^rr to -g-J-g- of an inch in their long 

 diameter, by about -^Vo f an ^ ncn * n width. 1 They contain 

 the true bone-corpuscles, which we will presently describe. 



Canaliculi. These are little wavy canals, connecting 

 the lacunae with each other and presenting a communication 

 between the first series of lacunae and the Haversian canals. 

 Each osteoplast presents from eighteen to twenty canaliculi 

 radiating from its borders. Their length is from -^ to ^-J-g- 

 of an inch, and their diameter about ^-g-^oir f an inch. 2 The 

 arrangement of the Haversian canals, lacunae, and canaliculi 

 is shown in Fig. 19. 



Fia. 19. 



Vascular canals and lacunae, seen in a transverse section of the dianhysis of the hn- 

 merus. Magnified two htindred diameters. 1, 1. 1, Section of the Haversian canals 

 2, Section of a longitudinal canal divided at the point of its anastomosis with a 

 transverse canal. Around the canals, cut across perpendicularly, are seen the lacunrc 

 (with their canaliculi), forming concentric rings. (SAPPEY, Traite d'anatomie Paris 

 1866, tome i., p. 79.) 



.Bone-cells or Corpuscles. By treating perfectly-fresh 

 specimens of bone with weak acid solutions, Virchow has 



1 SAPPEY, op. cit., p. 80. 



2 Idem., p. 81. 



