00 MANUAL OF HISTOLOGY. 



The white corpuscles of the blood are pre-eminently suited 

 for building tissue. When blood is organized, which occurs 

 not infrequently, the white corpuscles at once assume an im- 

 portant role, while the red are soon melted down into a homo- 

 geneous mass, that is usually absorbed. This change is ob- 

 served under various pathological conditions. 



Fibrous tissue. This substance, which is also known as 

 fibril] ated connective tissue, is the fully developed material 

 that has just been described. It occurs either in parallel 



FIG. 25. Reticular form of connective tissue. From the human umbilical cord. 



bundles or fascicles, in interlacing lamellae, or as a fenestrated 

 material containing larger or smaller openings. A special va- 

 riety, the reticular, is seen to great advantage in the umbilical 

 cord of an infant at birth (Fig. 25). 



If a cut be carried through the spongy portions of the cord, 

 it will be seen that the tissue is composed of bright, shining, 

 branching bundles, <#, superimposed upon which are a num- 

 ber of oval, flattened plates, a, at intervals ; about them is 



