306 HISTOLOGY OF THE MORBID PROCESSES. 



one point with the walls of the capillaries and reaching out in Col- 

 umns or bands among the cells of the granulation-tissue. Here they 

 may become united w r ith each other, forming loops that spring from 

 the same capillary vessel, or connect it with other capillaries. Sub- 

 sequently these solid columns or bands of cells become channelled, 

 the cells forming the walls of the new vessels, the lumina of which 

 communicate with those of the parent capillaries (Fig. 271). 



FIG. 271. 



New-formation of bloodvessels in granulation-tissue. (Birch-Hirschfeld.) 



The granulation-tissue thus formed is continuous with the adja- 

 cent uninjured fibrous tissues, and serves to separate the tissues that 

 have been killed or have undergone irrevocable degeneration from 

 the living tissues that lie beneath it. The dead mass is finally 

 loosened and cast oif, leaving a surface of growing granulations. 

 While the cells in the superficial portions of this granulation-tissue 

 continue to multiply and produce fresh, young, undifferentiated tis- 

 sue, the deeper portions undergo differentiation, the formative powers 

 of the cells being no longer preoccupied with the production of new 

 cells, but diverted to the elaboration of intercellular substances of 

 a fibrous character (Fig. 272). 



During this process the cells dwindle in size as the intercellular 

 substances accumulate between them, and may suffer complete extinc- 

 tion. This may be due to atrophy in consequence of pressure exerted 

 by the fibrous constituent of the intercellular substances, which has a 

 marked tendency to shrink as it becomes older. Another probable 

 reason for the disappearance of many of the cells may be the lack 

 of a well-defined lymphatic circulation in the granulation-tissue 

 and the young cicatrix, which, if it existed, would serve to assist 



