FORMATION OF LACUNA. 149 



ever been generally admitted by anatomists since 

 1850. Under the name of "nucleus" the bioplasm 

 had been observed in the lacunae of many specimens 

 of osseous tissue, and Tomes and De Morgan demon- 

 strated indications of these bodies in the lacunas of 

 fossil bone, in their paper published in the Phil. 

 Trans, in 1853. Subsequent investigations have 

 proved that in every kind of growing bone, at every 

 period of life, are numerous masses of bioplasm, with- 

 out which the formation of bone tissue could not have 

 taken place, and which are concerned in all the im- 

 portant changes going on in it during life. As long 

 as the masses of bioplasm are living, the changes 

 characteristic of living bone may take place, but if 

 these be dead in any part of the bone this soon 

 separates from the rest, and ceases for ever to be the 

 seat of vital changes. 



The masses of bioplasm are as necessary for the 

 production of bone as they are for the formation of 

 every other tissue. They are not directly concerned 

 in the precipitation of the calcareous matter, but in 

 their absence the production "of matrix would be 

 impossible. It is alone by the instrumentality of 

 these masses of bioplasm that the regular circulation 

 of fluids holding in solution the calcareous salts, is 

 maintained throughout every period of bone forma- 

 tion. By this process the regularity in the formation 

 of osseous tissue, which is so remarkable, is secured. 



The deposition of the inorganic salts is no doubt 

 due to physical and chemical change ; but the precise 

 locality of the precipitation, as well as the mode of 

 deposition of the calcareous particles, is determined 

 by actions (vital) of which the bioplasm or living 

 matter is the seat. 



21O. Formation of lacunae. The views of Kolliker 

 and Virchow. Kolliker considers that the capsule of 

 the cartilage cell and the "intercellular" matrix of 

 the temporary cartilage of developing bone become 



