CHAPTER XI 



GRANULATION TISSUE THE NORMAL ' GRANULOMA ' OF DEFENCE 



AND REPAIR 



THE formation of granulation tissue from fibrous tissue is one of 

 the most important defensive processes that occur in the animal 

 body. When the tendon of the heel is divided subcutaneously by 

 a tenotome in a rabbit the divided ends of the tendon separate 

 by a space of nearly f inch. One animal was killed twenty-four 

 hours after this little operation had been done aseptically, and the 

 separated ends of the tendon were found to be already joined by 

 a firm straw-coloured jelly, which filled the tendon sheath in the 

 form of a cylinder, which at its extremities enveloped the divided 

 ends of the tendon. There was but little effused blood, and it was 

 confined to the cut surfaces of the tendon. A tendon similarly 

 divided and removed with the uniting material at the end of forty- 

 eight hours, then fixed in a mixture of saturated perchloride of 

 mercury and 5 per cent, chromate of potassium (Foa's solution), 

 and examined in sections after staining with Ehrlich's haematoxylin 

 and e*osin, presents the different features shown in Fig. 27. Another 

 rabbit was killed four days after a tenotomy had been done, and the 

 state of the united medium, now fully formed granulation tissue, is 

 shown in Fig. 28. The series of events thus briefly indicated 

 offers several points for comment. The straw-coloured coagulum 

 that is present at the end of forty-eight hours can only be coagu- 

 lated plasma from the blood and lymph set free from the divided 

 vessels. That this coagulum, after forty-eight hours, is everywhere 

 traversed by a network of cells testifies to the rapidity of the process 



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