82 PRACTICAL MICROSCOPY. 



3. External limit of dentine. (Note here the deeply stained 

 granular line of Purkinje. This is the location of the interglobular 

 spaces. The deep color is due to the staining of their cell contents.) 



4. The striae of the dentine (dentinal canals and stained con- 

 tents). 



5. The laminated crusta. (The yellowish pink dots on the 

 lacunae.) 



(H.) 



6. Elements of the pulp, (a) The layer of odontoblasts (note 

 their internal processes connecting with other cells of the pulp; and 

 the external processes passing into the dentinal canals). (b) The 

 sparsely fibrillated character of the pulp tissue, (c) Sections of 

 vascular loops. (The nerve elements may be demonstrated, par- 

 ticularly if the section be made near the apex of the fang, where the 

 fibres are medullated. The terminal fibrillse are non-medullated.) 



7. Dentinal elements, (a) The dentinal canals, (b) The 

 dentinal sheath. (Better demonstrated in transverse sections.) (c) 

 Dentinal fibres. (In transverse sections the canals are well shown 

 lined with a membrane of extraordinary tenuity, with the fibre appear- 

 ing as a central dot.) (d) Fine dentinal fibres near the outer limit* 

 (e) Interglobular spaces. (An occasional cell may be made out 

 in the larger spaces. They were formerly supposed to contain a gelat- 

 inous material only. Note the connection between these spaces and 

 the termini of the dentinal fibres.) 



8. The Crusta Petrosa. (a) Its laminated formation, (b) 

 The lacunae, (c) Bone corpuscles in the last. (The canaliculi are 

 not well demonstrated here, as the tissue is very translucent and 

 feebly stained. These minute canals are better indicated in dried 

 bone. 



9. The periosteum. Note its dense fibrillar mesh work. 



