54 



FIFTH LECTURE. 



very delicate rings, which have a striking resemblance to an 

 elastic fibre. Cotton fibres undergo a very similar change on 

 the addition of ammoniac copper ; only, everything is here 

 more massive and easier to observe. 



The most difficult part in the investigation of the connective 

 tissue is formed by the cellular elements, the connective-tis- 

 sue corpuscles of an earlier period. After manifold strayings, 

 a greater light has only of late years been disseminated. 

 Since the cells were, as a rule, usually concealed by the 

 substance of the fasciculi, acetic acid was formerly generally 

 used for the recognition of the former. This, and even 

 water, immediately distorts the cells into caricatures. The 

 latter have been almost universally known and described for 

 tens of years ; and capital has been made of them ! 



The cellular elements are distinguished into non-essential 

 migratory, and essential fixed. The former are lymphoid 

 cells, which, having escaped from the blood and lymphatic 

 vessels, slowly wander through the channels of our tissue. 



The ordinary fixed connective-tissue cell appears as a 

 simple or complicated lamellar structure. An oval nucleus 

 is surrounded by some protoplasma. The thin structure 

 becomes extremely pale and veil-like at the periphery, 

 and runs out into points or fibrillar. Very frequently, how- 

 ever, there is also a vary- 

 ing number of lateral plates 

 resting at different angles 

 over the middle of these 

 chief plates (Fig. 55, a), so 

 that .a certain resemblance 

 to an irregular, crumpled 

 shovel edge is produced 

 (Ranvier, Waldeyer). Such 

 cells lie in the firm connec- 

 tive tissue, in the spaces 

 between the fasciculi, and have, according to our views, as- 

 sumed the described forms subsequent to the growth in thick- 

 ness of those fasciculi. The procedure may be illustrated by 



Fig. 55. — Cells of human connective tissue : a, 

 flat and shovel-shaped elements ; 6, coarse granu- 

 lar cells. 



