144 LIVING BIOPLASM OF BONE. 



were it not for these little canals or pores traversing 

 its substance. 



An elementary part of every kind of bone at a 

 very early period of its formation, consists of a mass 

 of bioplasm, surrounded by a certain pi^oportion of 

 gi'anular, homogeneous or more or less fibrous (?) 

 formed material. This last becomes tbe seat of 

 deposition of calcareous matter, wbicli proceeds in a 

 direction from vntliout imvards. The formation of 

 the canalicuh takes place in the same direction. We 

 shall find, contrary to the generally received opinion, 

 that the formation of these tubes commences not at a 

 point nearest to the bioplasm, the so-called " cell," as 

 has been repeatedly stated, but at a distance from it. 

 § 208. 



303. LiTiiig liioplasin of bone. — The difference 

 between dead bone and living hone is simply this : 

 in the first, formation of tissue has everywhere 

 ceased ; while in the last, it is still proceeding, and 

 around each mass of bioplasm the production of 

 matrix and the deposition of calcareous salts in the 

 matrix already formed is going on. These changes 

 may proceed very slowly, but in all living bone they 

 occur. The only matter in a living bone which is 

 actually alive is that which is ordinarily termed the 

 " nucletcs " or the " hone cell " in the space or lacuna, 

 and which is here spoken of a,s the bioplasm or living 

 matter. The fully-formed osseous tissue around, on 

 the other hand, is to all intents and purposes, as 

 devoid of Hfe while the bone yet remains a part of • 

 the living body, as after it has been removed, or after 

 the body has died. This small mass of bioplasm, 

 perhaps not more than one- twelfth of the bulk of the 

 proportion of bone tissue which belongs to it, alone 

 possesses active powers. This only can grow and 

 give rise to the formation of matrix. Bone cannot 

 produce bone any more than tendon can give rise to 

 tendon, or muscle form contractile tissue, but the 



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