338 INFLAMMATION. [BOOK i. 



dilated, eventually regain their calibre, and a normal circulation is 

 re-established. The migrated corpuscles move away from the 

 region, along the labyrinth of lymph spaces, and the surplus lymph 

 also passes away along the lymph spaces and lymphatic vessels. 



184. The condition of things however instead of passing off 

 may go on to a further stage. More and more white corpuscles, 

 arrested in their passage, crowd the channels and block the way, 

 so that though the vessels remain dilated the stream becomes 

 slower and slower, until at last it stops altogether and "stagnation" 

 or "stasis" sets in. The red corpuscles are driven in, often in 

 masses, among the white corpuscles and platelets, the distinction 

 between axial stream and peripheral zone becoming lost ; and 

 arteries, veins and capillaries, all distended, sometimes enormously 

 so, are filled with a mass of mingled red and white corpuscles 

 and platelets. When actual stagnation occurs the red corpuscles 

 run together so that their outlines are no longer distinguishable ; 

 they appear to become fused into a homogeneous red mass. 

 And it may now be observed that, not only white corpuscles but 

 also red corpuscles, make their way through the distended and 

 altered walls of the capillaries, chiefly, at all events, at the 

 junctions of the epithelioid plates, into the lymph spaces beyond. 

 This is spoken of as the diapedesis of the red corpuscles. 



This latter 'stagnation' stage of inflammation may be the prelude 

 to further mischief and indeed to the death of the inflamed tissue, 

 but it too like the earlier stages may pass away. As it passes away 

 the outlines of the corpuscles become once more distinct, those on 

 the venous side of the block gradually drop away into the neigh- 

 bouring currents, little by little the whole obstruction is removed, 

 and the current through the area is re-established. 



The slowing and final arrest of the blood current described 

 above is not due to any lessening of the heart's beat ; the arterial 

 pulsations, or at least the arterial flow, may be seen to be continued 

 in full force down to the affected area, and there to cease very 

 suddenly. It is not due to any constriction of the small arteries 

 increasing the peripheral resistance, for these continue dilated, 

 sometimes exceedingly so. It must therefore be due to some new 

 and unusual resistance occurring in the area itself, and there can be 

 no doubt that this is to be found in an increased tendency of the 

 corpuscles, especially of the white corpuscles, to stick to the sides 

 of the vessels. The increase of adhesiveness is not caused by any 

 change confined to the corpuscles themselves ; for if after a tem- 

 porary delay one set of corpuscles has managed to pass away from 

 the affected area, the next set of corpuscles brought to the area in 

 the blood stream is subjected to the same delay and the same ap- 

 parent fusion. The cause of the increased adhesiveness must 

 therefore lie in the walls of the blood vessels or in the tissue of 

 which these form a part. That the increased adhesion is due to 

 the vascular walls and not primarily to the corpuscles themselves 



