654 THE TEETH. 



with chloride of gold. The apparently structureless, or indistinctly granular, 

 myxomatous basis-substance, held in the meshes of the myxomatous reticu- 

 lum, proves to be a reticular structure, just as well as the bioplasson itself. 



The second variety of pericementum is built up by fibrous connective 

 tissue, which prevails in adults and persons of advanced age. The bundles 

 of the fibrous connective tissue may be uniform in width throughout the 

 whole pericementum, or there exists a zone of myxomatous or indistinctly 

 fibrous character close around the cementum. The bundles are built up by a 

 number of fibers which hold a varying amount of plastids as a rule, more 

 numerous the nearer to the cementum. On the latter there may be found 

 rows of osteoblasts or scattered bioplasson bodies alternating with bundles of 

 a delicate connective tissue, which are directly attached to the cementum. 

 In a few instances I have seen rows of osteoblasts, the refracting power 

 of which was considerably augmented. Such corpuscles looked shining and 

 structureless, evidently on account of a deposition of lime-salts. The fibrous 

 variety of the pericementum also contains fat-globules, sometimes in a sur- 

 prisingly large quantity. 



High magnifying powers of the microscope reveal a structure of the fibrous 

 connective tissue, as follows : The fibers, a certain number of which combine 

 in the formation of a bundle, are delicate spindles, directly connected with 

 each other at their pointed ends. These spindles are separated from each 

 other by a narrow layer of a light cement-substance. The interstices between 

 the spindles are traversed in a vertical direction by extremely minute threads 

 every way analogous to the thorns in the cement-substance surrounding epi- 

 thelial elements. These threads, in many instances, are visible in specimens 

 hardened by the chromic acid solution ; they become very plain when thin 

 sections have been immersed in a half per cent, solution of chloride of gold 

 for one or two hours, or until the specimen has assumed a dark violet color. 

 If the stain be complete, we also recognize that the spindles are not homoge- 

 neous, as they look in fresh, unstained specimens, but are rather traversed by 

 a delicate, dark violet reticulum, the points of intersection of which are 

 slightly thickened, and thus represent granules. (See Fig. 287.) 



Between the spindles of the basis-substance plastids are seen the so- 

 called " connective-tissue cells." Some of these bodies exhibit shining, com- 

 pact, oblong nuclei, with a certain amount of surrounding bioplasson, while 

 others are devoid of nuclei, and split into spindle-shaped or polygonal lumps, 

 which in size and shape fully correspond to the elementary formations of the 

 fibrous basis-substance. In some instances, between the cementum and the 

 osteoblasts there is interposed a small layer of fibrous basis-substance in the 

 shape of delicate, slender spindles. 



In its juvenile condition the pericementum represents a myxomatous 

 connective tissue, the fibrous portion of which is comparatively scanty, while 

 the bioplasson portion prevails. In this instance two varieties of basis-sub- 

 stance occur, viz. : the fibrous, building up the reticulum, and the myxo- 

 matous, filling a certain portion of the meshes. This condition arises from 

 , the indifferent or embryonal tissue, not only in the pericementum, but in all 

 formations of connective tissue which, when fully developed, exhibit a fibrous 

 structure. The only way to explain the formation of the myxomatous tissue 

 is, that a part of the substance constituting the embryonal elements remains 

 unchanged, a part is transformed into spindles of the myxomatous reticulum, 

 and a part into. myxomatous basis-substance. 



