198 MICROSCOPIC ANATOMY OF THE TEETH 



endoplasm or cytoplasm of the cell. Apart from the 

 processes of the cell, there would appear to be a distinct 

 development of fibres within the exoplasm, as seen in the 

 so-called Wharton's jelly of the umbilical cord, which, as 

 previously stated, has a strong histological resemblance to 

 the tissue of the developing tooth-pulp. 



That these large cells of the tooth- pulp have long inter- 

 communicating processes is very evident in preparations 

 of actively growing pulps (figs. 110 and 111). These photo- 



FIG. 110. Human tooth-pulp. Open-ended premolar (pyridin silvei). 

 Large connective tissue cells and processes. ( x 450. ) 



graphs were taken from an erupted human premolar in 

 which the root portion was still in an early stage of develop- 

 ment. The preparations were stained by the pyridin silver 

 method, and the pulp is seen to be crowded with large 

 cells of very various sizes and shapes, which are provided 

 with long connecting processes interlacing in the pulp. 

 Their nuclei are very conspicuous and the fibrillation is seen 

 to pass across the interior of the cell. This is very evident 

 in the part of the preparation from which fig. 110 was taken, 

 but the strong yellow colour of the section prevents this 

 fibrillation being distinctly brought out without over- 

 exposure of the rest of the image. There is evidence in these 



