THE TEETH. 



653 



lar structure, termed myxomatous ; the other is altogether fibrous. The 

 myxomatous variety I have met with, as a rule, in young individuals. It con- 

 sists of delicate fibers, or bundles of fibers in a net-like arrangement, which, 

 in many instances, are supplied with round or oblong nuclei at the points of 

 intersection. The meshes contain either a hyaline, apparently structureless, 

 sometimes finely granular, basis-substance, or they hold plastids provided 

 with a varying number of nuclei. The nearer to the cementum, the narrower 

 is the myxomatous reticulum, and the smaller, therefore, are the inclosed plas- 

 tids. The latter, in the immediate vicinity of the cementum, stand in more or 

 less regular rows, entirely analogous to the bioplasson bodies around the 

 developing bony tissue, known, since Gegenbaur, as u osteoblasts." Some of 

 the meshes of the myxomatous tissue are considerably larger, and contain 

 multinuclear bodies. Other meshes hold fat-globules, which, in specimens 



r C 



......',...., !...! ;.l,:/..L',::.,:7. ;ilL,t L .:,,:> 



FIG. 286. PERICEMENTUM OF MYXOMATOUS STRUCTURE. 



D, dentine ; C, cementum of neck ; P, pericementuin ; M, multinuclear body ; V, capillary 

 blood-vessel ; JT, fat-globule with a vacuole. Magnified 500 diameters. 



preserved and hardened in a solution of chromic acid, very often contain 

 closed spaces so-called vacuoles. The myxomatous reticulum is traversed 

 by numerous blood-vessels, mainly capillaries and veins, some of which can 

 be seen entering the medullary spaces of the compact bone of the wall of the 

 alveolus and in connection with the capillary system of the cancellous portion 

 of the alveolus. I have met with but few nerve-fibers in my specimens. (See 

 Fig 286.) 



High amplification of the microscope plainly demonstrates the delicate, 

 reticular structure of all plastids, the reticulum being visible not only in the 

 contents of the meshes, but also within the fibers of the myxomatous reticu- 

 lum. The latter feature is recognizable best on specimens deeply stained 



