THE TEETH. 



655 



The final result may be, especially in pericementum, either a jelly-like 

 myxomatous, or a solid, fibrous basis-substance. The living portion, at all 

 events, remains untouched by the chemical alteration of the lifeless fluid. 



On this theory the transformation of the myxomatous tissue of juvenile into 

 the fibrous tissue of adult age is easily explicable. We only need assume a 

 dissolution or liquefaction of the already formed basis-substance in order 

 to understand the reappearance of the embryonal condition at a certain 

 stage of development. The myxomatous tissue as such never changes 

 directly into a fibrous one, but must first be reduced into its embryonal 

 or bioplasson condition, and from this in turn fibrous connective tissue may 

 arise. The latter process is explained by the splitting and elongation of the 

 plastids into spindles which become solidified ; in other words, the lifeless 

 fluid is transformed into a gluey basis-substance. 



At no time has the reticulum of the living matter been interrupted or torn ; 

 the pericementum has never ceased to be a tissue either in its embryonal, 



FIG. 287. PERICEMENTUM OF FIBROUS STRUCTURE. 



C, cementum of root ; PL, pericemeiitum, the fibers of which are built up by spindles, in 

 longitudinal section ; PF, pericemeiitum, the elementary spindles of which are finer and cut 

 obliquely ; P 1 , P%, bioplasson bodies, either so-called connective-tissue corpuscles or so- 

 called osteoblasts. Magnified 1200 diameters. 



myxomatous, or fibrous condition. On the theory here explained, all changes 

 in inflammatory processes of the pericementum may be easily understood. 



(B) Pericementitis. Plastic Inflammation and New Formation. Practitioners 

 are aware that pericementitis presents itself in two forms, evidently accord- 

 ing to the intensity of the inflammatory process. One form is the plastic, 

 which, if repeatedly recurring, leads to a new formation of connective tissue, 

 the so-called hyperplasia, or hypertrophy ; the other and more severe form 

 is the suppurative pericementitis, which inevitably leads to a more or less 

 extensive destruction of the pericementum, to death of the pulp, and not 

 infrequently to necrosis of the alveolar process. 



Pericementitis, in its mildest degree, with lower powers of the microscope, 

 is recognizable by the presence of nests, filled with medullary elements, in 



