ON THE STRUCTURE OF TENDON. 135 



US note several other points in the anatomy of the tendon — 

 first, that the young tendon possesses relatively more cells than 

 the adult one ; secondly, that the length of the cell-plate in the 

 adult tendon usually exceeds their breadth ; and lastly, that in 

 the adult tendon the cell-plates are more branched in the 

 direction of the long axis of the bundles than in the trans- 

 verse one. Putting these facts together, I believe I am 

 justified in assuming that in the growth of the fibril-bundles 

 in length and thickness, the cell-plates become removed from 

 each other, yet continue their mutual connection by commu- 

 nicating processes corresponding to the prevailing growth of 

 the fibril-bundle ; the cell-plates will also be longer than broad, 

 and will similarly come to possess longer processes in the 

 long axis of the tendon than in the other. 



But it must be stated that during the growth of the fibril- 

 bundles there is another change in the cell-plates besides 

 that which has just been described, which consists in this — 

 that one cell -plate divides into a chain of cell-plates, which, 

 while they gradually separate, remain connected to each other 

 by processes. And it must also be stated, on the other hand, 

 that a cell already branched at the extremities will itself again 

 divide across, and the originating divisions separate. In favour 

 of this view are all those intermediate appearances Avhicli w'e 

 meet with in the half grown and in the adult tendon, viz. cell 

 stripes, in which here aind there the individual members, ar- 

 ranged behind each other, stand isolated and branched, as well 

 as places where a row of cell-plates occurs of which only 

 the two terminal ones are branched, and that terminally only, 

 while the others are mutually joined by straight lines. 



If Boll makes a distinction between the cells of the grow- 

 ing and of the adult tendon in this respect, that in the former 

 the cells are more protoplasmic in nature than in the latter, 

 Avhere they should be considered as representing elastic 

 plates, then I must say that I cannot agree with him. And 

 if he calls the cells of the tendinous tissue endothelium, then 

 here again I can agree with him only so far as this ; — that in 

 the young tendon the cell-plates possess an arrangement which 

 is just comparable to that of endothelium. As for the grown 

 tendon, its cells can be called endothelial only in so far as 

 they represent plates consisting of granular protoplasm, and 

 in some places are less branched and more close to each other 

 — that they only rest in a line like endothelium, and differ in 

 their arrangement in no respect from those cells found in the 

 tissue of the serous membrane of grown animals. (Com- 

 pare " Preliminary Communication," &c., by Dr. Klein and 

 Dr. Bur don Sanderson, in this Journal, p. 142. 



