DENTINE 275 



as matrix or foundation fibres in which the lime salts are 

 deposited by the agency of the odontoblasts. 1 



That connective-tissue fibres from the pulp in young 

 teeth with uncompleted roots are sometimes seen passing 

 in a radiating manner into the dentine is shown in fig. 171. 

 The specimen from which this photograph was taken was 

 stained with Van Giesen stain, which brings out connective 

 tissue very conspicuously. The fibres can be seen passing 

 from the pulp and spreading out into the dentine ; deeper 

 within its substance they pass, not parallel, but more or less 

 at right angles to the dentinal tubes. The appearance in 

 these sections of small cells apparently in intimate relation 

 with these fibres when the section passes in this direction 

 is a little puzzling, as the odontoblasts are not visible as 

 a distinct layer where these rows of cells are evident, although 

 their nuclei can be seen in places lying between them. 

 This appearance was illustrated in the author's paper of 

 1892, where he described the cells as being destitute of pro- 

 cesses ; a more selective connective -tissue stain has, however, 

 since shown that a distinct cytoplasm surrounds these 

 nuclei, and that processes of the cell are produced from it 

 extending on every side (fig. 171 at a). In the later stages 

 of dentine formation, when these penetrating fibres are seen 

 in the dentine, they appear to be partially impregnated 

 with lime salts in advance of the general line of calcification, 

 and the question arises whether these smaller cells take any 

 part in the calcification of the matrix. 



In the paper above referred to the author expressed the 

 opinion that ' These cells secrete a material which calcifies 

 along the line of the odontogenic fibres ', but it is very 

 difficult to decide if this is the case or not. 



1 In the new edition of his Histology (1919) Professor Hopewell Smith 

 says : ' It is probable that these connective-tissue fibres are considered 

 by Howard Mummery to be the terminations of the myelinic nerve fibres 

 of the pulp.' It is difficult to understand how any histologist could make 

 such a mistake. V. Korff described these fibres only in young developing 

 teeth at the very first commencement of calcification, and although a few 

 are now and then to be met with in older pulps they are easily distinguished 

 (see fig. 175). The nerve fibres shown by the author arise from unmistakable 

 medullated nerve trunks, and moreover the fibres of V. Korff take the stain 

 very differently and much more faintly in gold preparations. 



