272 



THE CELL-THEORY 



becomes stronger and stronger as we proceed lower down, until it ends 

 in an apparent fibrillation. A chemical change has at the same time 

 taken place, so that in this portion the striated part of the periplast 

 is swollen up more or less by acetic acid, the walls of the cavities 

 remaining unaffected, and thence becoming more distinct ; while in the 

 portion A, the whole periplast was nearly equally insensible to this 

 re-agent. The portion C, nearest the tendon, and passing into it, is 

 completely tendinous in its structure. The periplast exhibits strong 

 fibrillation, and is very sensitive to acetic acid, while not only the walls 



of the cavities, but the interme- 

 diate periplast, in certain direc- 

 tions, which radiate irregularly 

 from them, have changed into a 

 substance which resists acetic acid 

 even more than before, and is in 

 fact elastic tissue. Compare this 

 process with that which we have 

 seen to be undergone by the col- 

 lenchyma of the beetroot, and we 

 have the fibrillation of the outer 

 portion of the periplast around 

 each endoplast, and its conversion 

 into collagen, answering to the 

 lamination of the " intercellular 

 substance," and its conversion into- 

 a vegetable gelatinous matter, while 

 the elastic corresponds with the 

 cellulose inner wall. 



The testimony of numerous 

 observers agrees that cartilage is 

 converted into connective tissue 

 in the way described. Professor 

 Kolliker, who unwillingly admits 

 the fact, suggests, nevertheless, that such connective tissue as this is 

 not true connective tissue, inasmuch as it presents differences in its 

 mode of development, the collagenous element in the latter being 

 always developed from cells.'- 



Now, we might be inclined to ask, if the substance of the tendo- 

 Achillis is not connective tissue, but only " tduschend aknlich," what is ? 

 But it is better to attack Prof Kolliker's stronghold, the areolated 



Fig. 4. 



Stellate "cells" of young connective tissue 

 from the actinenchyma of the enamel 

 organ of the calf. 



1 Handbuch, pp. 58, 59, 218. 



