40 THE ESSENTIALS OF HISTOLOGY 



both white and elastic, are deposited in this ground- substance, the 

 elastic substance usually in the form of granules (fig. 47, g), which 



FIG. 46. JELLY OF WHARTON. 



r, ramified cells intercommunicating by their branches ; I, a row of lymph-cells ; 

 f t fibres developing in the ground-substance. 



subsequently become connected together into elastic fibres or laminae, 

 as the case may be, the white fibres appearing at first in the form of 

 very fine bundles, which afterwards become gradually larger ; so that 

 in fibrous tissue the whole ground- substance is eventually pervaded by 



FIG. 47. DEVELOPMENT OF ELASTIC TISSUE BY DEPOSITION OF FINE 

 GRANULES. 



gr, fibres being formed of rows of 'elastin' granules ; p, flat platelike expansion of 

 elastic substance formed by the fusion of 'elastin ' granules. 



them, and the cells of the tissue become squeezed up into the intervals 

 between them. Before any considerable development of fibres has 

 taken place, the embryonic connective tissue has a jelly-like appear- 

 ance ; in this form it occurs in the umbilical cord, where it is known 

 as the jelly of Wharton (fig. 46). 



