250 CONNECTIVE TISSUE. 



shaft-bones of growing and adult animals, we encounter numer- 

 ous circular fields, containing one or more bone-corpuscles. We 

 also find within the medullary spaces globular bodies, containing 

 several nuclei, or only a number of nucleoli, sometimes exhibit- 

 ing a uniform coarse granulation, due to the large points of 

 intersection of the living matter. These masses, termed " myelo- 

 plaxes " by their discoverer, Ch. Robin, are likewise the predeces- 

 sors of bone formation, as I demonstrated in 1872.* Here a 

 portion of the protoplasma is transformed into basis-substance, 

 which at once becomes calcified, while the central portion is not 

 changed into basis-substance, and remains as the bone-corpuscle 

 or the bone-cell. (See Fig. 101.) 



We often find lenticular, multinuclear masses in the shaft- 

 bones of growing animals, not only in the epiphysis at the 

 borders of medullary spaces, but also in the vascular canals of 

 the diaphysis. Such masses are separated from their neighbors 

 by light rims, but also connected with them by delicate spokes 

 of living matter. These are the first traces of a third kind of 

 tissue-units of the bone, the lone-globules, which are known by 

 Virchow to be the cell-territories proper. Each of these origi- 

 nates from a multinuclear mass, and each contains one or more 

 bone -corpuscles. 



Formations of this globular variety are met with also in the 

 calcareous nucleus of the epiphyseal cartilage, at the ossifying 

 border of the diaphyseal or intermediate cartilage, " and in the 

 centers of calcification of short bones." [The last words are 

 newly added.] (See Fig. 102.) 



The multinuclear bodies, which have sprung from medullary 

 elements, are, therefore, the regular bone-formers, appearing 

 first around the trabeculaB of the calcified basis-substance of 

 cartilage, and later independently of. other formations. It 

 depends entirely on the original shape of the medullary lumps, 

 whether the bone-tissue assumes a striated, lamellated, or globular 

 structure. 



Bone, therefore, as well as all other varieties of connective 

 tissue, is a product of the medullary or embryonal tissue, the 

 elements of which either split into delicate spindles, resulting in 

 the formation of a striated basis-substance, or coalesce into len- 

 ticular masses, a number of which unite in the construction of 

 a lamella, or else coalesce into globular masses, from which arise 

 the globular territorial formations of the bone-tissue. 



* " Studien am Knochen u. Knorpel," Mediz. Jahrb., 1872. 



