102". : MICROSCOPIC ANATOMY OF THE TEETH 



remaining fourth appearing as though they were between 

 them, but he considers it is a priori highly improbable that 

 they occupy both positions. Von Ebner (66) considers that 

 the tubes lie between the prisms in the interprismatic spaces, 

 and his figure of transverse marsupial enamel shows, accord- 

 ing to C. S. Tomes, that all but one appear to do so ; the 

 drawing, however, scarcely indicates that one lies within 

 the prism, and any appearance of its so doing may probably 



FIG. 57. Transverse section of enamel of Macro pus (injected with 

 fuchsin from the pulp cavity). Interprismatic substance strongly stained 

 and transverse sections of enamel tubes more deeply stained and within 

 the interprismatic substance. ( x 800. ) 



be fully explained as being due to the thickness of the 

 section. 



J. Tomes (17 a) and Kolliker considered there was no doubt 

 that the dentinal tubes pass into the enamel. This is denied 

 by Waldeyer. Von Ebner agrees with Kolliker and J. Tomes. 

 The passage of tubes from the dentine to the enamel is held 

 by Von Ebner to be analogous, to the ingrowth of nerve 

 fibres into epithelium. He says it is evident that in young 

 marsupial teeth the canals run in the interprismatic sub- 

 stance. By decalcification experiments he showed that the 

 tubes held together and had much the appearance of elastic 



