242 CONNECTIVE TISSUE. 



bony tissue are formed one in each epiphysis and one in the 

 diaphysis. The outer portion of the epiphyseal cartilage is the 

 articular cartilage proper 5 the cartilaginous portion between 

 the epiphysis and the diaphysis is termed the diaphyseal or 

 intermediate cartilage, which in human beings completely disap- 

 pears about the twentieth year of life. 



(~b) Formation of Medullary Tissue. The cartilage corpuscles 

 close above the place of calcification always have a coarse gran- 

 ular appearance, and are without a distinct nucleus. We under- 

 stand from this that the bioplasson of the corpuscle has increased 

 in amount, and thus begins a retrogression toward the juvenile 

 condition. In the spaces surrounded by calcified basis-substance 

 the cartilage corpuscles assume a very coarse granulation ; many 

 of them are nearly homogeneous, have a bright and vacuoled 

 appearance, and are furthermore marked by radiating offshoots. 

 (See Fig. 97.) 



At the same time the cartilage corpuscles increase in bulk, 

 also, by the addition of living matter, which, after the liquefac- 

 tion of the basis-substance, simply re-appears from where it before 

 was concealed. This re-appearance of living matter is indicated 

 first by a somewhat coarser granulation of the basis-substance, 

 and subsequently by the formation of new lines of demarkation, 

 corresponding to the liquefied portion of the basis-substance. 

 Even with moderate powers of the microscope all stages of the 

 re-appearance of bioplasson are traceable, from a distinct granu- 

 lation of the basis-substance up to the formation of fields exhib- 

 iting the features which in former times were termed " pale 

 protoplasm." Such fields either surround the original cartilage 

 corpuscle, or are joined to a part of the corpuscle. If the razor 

 has struck the peripheral portions in a space surrounded by the 

 calcified frame, only pale granular bioplasson is visible, and 

 there will be seen basis-substance alone if the section reached 

 the outermost portion. 



The next stage is the splitting of the bioplasson masses into 

 numerous smaller indifferent i. e., embryonal or medullary 

 corpuscles, each of which assumes a coarse granulation. It is 

 obvious that at first only those embryonal corpuscles will appear 

 which once themselves took part in the formation of the terri- 

 tory. By an increase of the bulk of their bioplasson these cor- 

 puscles become nucleated, and at first are finely, and later 

 coarsely, granular. Small lumps of bioplasson may also show 

 themselves, of a homogeneous appearance, a high degree of luster, 



