80 MICROSCOPIC ANATOMY OF THE TEETH 



to be no reason for considering them to be pathological, for 

 they are seen in well-formed teeth, sound in other respects, 

 and are conspicuous in the densely calcified enamel of the 

 teeth of prehistoric races. In several sections of human 

 teeth prepared by the author by the Weil process these 

 spindles are not confined to the immediate margin of the 

 dentine, but pass very deeply into the substance of the 

 enamel. The contents of these spaces are difficult to inter- 

 pret ; they usually appear to consist of amorphous granular 

 matter, appearing quite dark, almost black, in sections. 

 Some, however, are quite clear and transparent, and when 

 stained from the dentine by the fuchsin method show a 

 clear uniform coloration. Their communication with the 

 dentine is evidenced by the passage of the stain from the 

 tubes into their interior and by bubbles of air carried 

 by the stain to their farther extremities (fig. 37). Homer 

 {15) describes and figures fine corpuscles in these spindles 

 which he considers to be nerve-end bodies forming the 

 termination of nerve fibres in the dentinal tubes. As nerve 

 fibres traverse the dentinal tubes it does not seem improbable 

 that they should also penetrate any spaces in the enamel 

 with which the tubes communicate, but although rounded 

 bodies are certainly occasionally to be seen in these spindles 

 they are hardly sufficiently definite to be convincing. The 

 author found appearances very suggestive of these fine 

 corpuscles connected by fine thread-like processes in one 

 of the spindles of a tooth from the Stone Age (fig. 36), and 

 it seems highly probable that such round bodies and their 

 connecting strands may be caused by the arrangement of 

 the granular contents of the spindles. Certainly in the 

 majority of instances they have no appearance of being 

 filled by any organic material. 



Walkhoff holds that there is an absorption of the first- 

 formed dentine, and some of the tubes, escaping absorption, 

 persist as these spindles and their connecting dentinal 

 tubes. This would not appear to account for the size and 

 shape of these spaces, and it is a little difficult to understand 

 by what agencies such an absorption occurs. 



As described in a paper on the* tubular enamel of mar- 

 supials (11&) the author found apparently identical spaces 



