DENTINE 271 



blasts. It is difficult to trace these fine fibres within the 

 clear odontogenic zone, but in the tooth of the calf kept for 

 a long time in chromic acid they are very distinctly visible 

 (fig. 168). These observations were very clearly corroborated 

 by the examination of sections of the incisor teeth of a rat 

 prepared by the Weil process. A very strong connective 

 tissue is seen in the pulp, and an open-meshed reticulum 

 of connective-tissue fibres at the margin of the dentine 

 surrounded by small cells similar in appearance to those 

 of the main substance of the pulp. In these specimens 

 the fibres can be clearly traced into the formed dentine. 



It has been recently stated * that the author has receded from his view 

 of the part taken by the odontoblasts in the calcification of the dentine, 

 as expressed in his paper in 1892 (15 a), and it is made to appear that he 

 did not then look upon the odontoblasts as the calcifying cells ; but in 

 that paper he speaks of the dentine as a tissue ' which, according to the 

 view of secretion here maintained, is a material elaborated by the odontoblasts 

 and other cells, upon a connective-tissue foundation '. He never considered 

 the odontoblasts to have any but a calcifying function, but considered 

 that other small cells found in the pulp also took some part in the produc- 

 tion of the matrix, and recent observations, as shown in fig. 171, have con- 

 firmed him in that conclusion. Nowhere in the paper referred to or else- 

 where has he denied the principal part taken by the odontoblasts in the 

 calcifying process, and never at any time has he considered that sensation 

 was conducted by the dentinal fibril, as this criticism might appear to 

 suggest. 



In the rat the fibrous strands are very distinct within 

 the formed dentine, forming a band of a slightly darker 

 appearance than the rest of the dentine and fading away 

 in the deeper parts of the tissue approaching the enamel 

 (fig. 172). 



The incorporation of connective-tissue fibres in the 

 forming dentine of the Elephant is very evident (fig. 173), 

 and, as described in considering the development of vaso- 

 dentine, a very abundant connective tissue is incorporated 

 in the tooth of the Hake, showing that in fish, as well as in 

 several orders of the Mammalia and in man, connective tissue 

 forms a framework or basis to the dentine (fig. 181). 



Von Korff in 1905 published a paper (13) in which he 



1 A. Hopewell Smith, Normal and Pathological Histology of the Mouth, 

 vol. i, p. 290 (1919). 



