"outline" of the cartilage "cell." 121 



ready explanation upon the view of the formation of 

 cartilage which I hare taught. As growth proceeds, 

 the deposition of cartilaginous tissue takes place more 

 slowly, while, by the condensation of that which has 

 been already formed, room for the addition of new 

 tissue is obtained. As the cartilage approaches its 

 fully formed state, the tension resulting' from the 

 deposition of new tissue containing much fluid imme- 

 diately around the bioplasm gives rise to a slight 

 difierence in refraction of the formed material in this 

 situation, and it appears glistening and more trans- 

 lucent than the tissue generally. 



m. " Outline " of the cartilase " ceU." — It not 

 unfrequently happens that, in adult cartilage, the 

 bioplasm becomes detached from the formed material, 

 and appears as a spherical or oval body with a dark 

 outline, lying in a cavity (vacuole or closed space) in 

 the so-called matrix of the cartilage. The surface of 

 the mass of bioplasm may afterwards become further 

 condensed, and thus results the appearance which 

 has led many to the cod elusion that a true cell wall 

 or cell membrane encloses the remains of the bioplasm 

 of the cartilao'e. The examination of old cartilaofe in 

 which these changes have occurred has led many 

 observers to infer that complete "cells" occupied 

 spaces scooped out in the matrix, while others thought 

 that these cells were first formed, and the matrix 

 deposited from the blood in the intervals between 

 them independent of any cell action whatever. 



Ita. Changes in matrix after its formation. — After 

 cartilage tissue has been formed it often undergoes 

 a certain amount of change. A fibrous appearance 

 sometimes arises in that part of the matrix which 

 was first foi'med. This probably depends upon con- 

 traction taking place in the oldest part of the formed 

 material, but in certain forms of cartilage fibres are 

 developed from distinct masses of bioplasm lying in 

 the interspaces between those which are termed the 



