A " CELL" OF CARTILAGE OR TENDON. 223 



striking example is given. The specimen was taken from 

 the deeper portion of the conjunctival epithelium of man. 

 Not only is there no indication of division into distinct 

 cells, but the structure would be described as a " matrix " 

 exhibiting spaces occupied by the masses of bioplasm. As 

 will be noticed, the arrangement exactly corresponds with 

 that existing in the case of cartilage, fig. 3, and the masses 

 of bioplasm with, or without, a thin investment of formed 

 material may be removed just as in that tissue. 



It is therefore, clearly erroneous to consider cartilage 

 and epithelium as representatives of different classes of 

 tissues. The analogy between them will be at once under- 

 stood by a glance at fig. 2, and fig. 3, PI. VI, which have 

 been carefully copied from actual specimens. In fig. i, a 

 portion of older epithelium from the same surface is repre- 

 sented. In this, each mass of bioplasm is invested with its 

 own layers of formed material, and these are distinct from 

 neighbouring portions. A " cell," or elementary part of 

 fully-formed cartilage and tendon, consists of a mass of 

 bioplasm, with a proportion of formed material around it. 

 A line passing midway between the several masses of bio- 

 plasm would mark roughly the limit of the formed material, 

 corresponding to each particular mass of bioplasm, and 

 this would correspond with the outer part of the surface or 

 boundary of the epithelial cell. 



In order to understand the true relation of the so-called 

 intercellular substance of cartilage or tendon to the bio- 

 plasts, it is necessary to study the tissue at different ages. 

 At an early period of development, these tissues appear to 

 consist of masses of bioplasm only. As development ad- 

 vances, the formed material increases, and the bioplasts 



