298 MICROSCOPIC ANATOMY OF THE TEETH 



between the little flakes above described, their processes 

 passing between them. These are the more faintly stained 

 cells seen between the flakes in fig. 194. 



Schafer (Microscopic Anatomy) says : ' Osteoblasts are 

 probably specially modified connective-tissue corpuscles, 

 perhaps of the nature of plasma cells ; but after being 

 included in the lacunae they may undoubtedly be regarded 

 as homologous with the lamellar cells of connective tissue. 



d 



FIG. 193. The penetrating fibres of Sharpey in forming cement, osteo- 

 blasts lying between them. s. Remains of Hertwig's epithelial sheath ; 

 d. dentine ; c. cement. ( x 450.) 



It is not probable that they are produced from leucocytes, 

 as suggested by Kassander ' (5). 



Calcification. Two different views have been held as to the 

 mode of calcification in bone and cement, one being that the 

 osteoblasts are actually converted into bony substance, the 

 other that they secrete the calcifying material. 



A similar controversy has been held over the mode of 

 deposition of enamel and dentine, but the view more 

 generally held with regard to the process occurring in bone 

 is in harmony with that chiefly received in reference to the 

 other tissues of the tooth, that it is formed by the secretion 

 of a material which calcifies and not by an actual conversion 



