CHAPTER VII. 



HORSES' TEETH UXDER THE MICROSCOPE. 



The Dentinal Tubes, Enamel Fibers, and Cemental Canals De- 

 scribed and Contrasted. 



Prof. Richard Owen's description of the micro- 

 scopical appearance of horses' teetli, like the extracts 

 already made from liis works, is both interesting and 

 profound. The teeth described are illustrated in the 

 second volume of the " Odontography," the section of 

 the molar being magnified three hundred linear diam- 

 eters; that of the incisor, however, is not magnified. 

 In the first volume (pp. 576-7-8) Prof. Owen says: 



" The body of the long molar teeth of the horse 

 consists of columns of fine-tubed, unvascular dentine, 

 coated by enamel, which descends in deep folds into 

 the substance of the teeth. The enamel is covered 

 by cement, thickest in the interspaces of the inflected 

 enamel-folds and upon the crowns of the molars, where 

 it is permeated by vascular canals, thinnest on the 

 crowns of the canines and incisors. At the roots of 

 these teeth, and on those developed from the w^orn- 

 down molars, the dentine is immediately invested by 

 cement. 



" In a vertical section of the incisor, as in Plate 136, 

 Fig. 11, the pulp-cavity, contracting as it approaches 



