1074 



PHYSIOLOGY 



Fig. 494). The prolongation enlarges on the outer side of the vessel, while 

 the portion of the leucocyte within the vessel becomes smaller, so that filially 

 the whole leucocyte passes through and lies in the lymph spaces outside 

 the capillary. In the course of five or six hours all the capillaries and small 

 veins in the neighbourhood of the injury may show a crowd of leucocytes 





FIQ. 493. Inflamed mesentery of frog, to show margination of leucocytes in the 

 inflamed capillaries, a ; migration of leucocytes, & ; escape of red corpuscles, c : 

 accumulation of leucocytes outside the capillaries, d. (From AD AMI after 



RlBBERT.) 



along their outer surfaces. The use of this emigration seems to be to 

 remove the tissue injured by the primary lesion. As soon as this is effected, 

 regeneration of the injured tissue occurs by a proliferation of the connective 

 tissue corpuscles and the epithelium, while the leucocytes move away and 

 disappear. The essential phagocytic character of the inflammatory process 

 may be shown if the primary lesion be attended with infection. Thus if a 

 small quantity of the staphylococcus be injected into the subcutaneous tissue 



FIG. 494. Emigration of leucocytes through capillary wall. (ARNOLD.) 



of the rabbit, the vessels surrounding the point of injection may within four 

 hours be found densely filled with corpuscles. In ten hours' time the leuco- 

 cytes are present in large numbers outside the vessels, while the injected 

 cocci have spread for some distance along the lymphatic spaces and, while 

 partly free, have been to a large extent ingested by the leucocytes. In 

 twenty hours' time the connective tissue fibrils at the point of injection are 

 found to be widely separated by the aggregation of leucocytes. In forty- 

 eight hours' time a well-defined abscess is produced. At the centre all 

 traces of previous connective tissue have disappeared and its place has 

 been taken by a dense mass of leucocytes, many in a state of degeneration, 



