DISTINCTION BETWEEN CONGESTION AND INFLAMMATION. 447 



we are familiar as one of the products of inflammation. After 

 the pinch, then, we have had merely congestion; after the 

 caustic, inHaiumation. But in both we have had a similar dila- 

 tation in the calibre of the vessels, a similar increase in the 

 velocity of the circulation. Wliere, then, are we to draw tlie 

 line between congestion and inflanunation ? This question has 

 been well answered by Sir James Paget, who says that the line 

 appears to be crossed " when the cii'culation, which was rapid, 

 begins to grow slower without any diminution, but it may be 

 with an increase, in the size of the vessels." According to 

 Cohnheim, the clianges which are observed in the diameter of the 

 vessels are mere accessories, and not integral parts of the 

 inflammatory process ; and he also makes the slowing of the 

 circulation and stasis coincide with the commencement of 

 inflammation.* 



There is no doubt about the fact, but it is difficult to see why 

 the blood corpuscles should stand still in a vessel where there 

 is no apparent obstruction, and many explanations have been 

 advanced to account for the phenomenon. The one which finds 

 most general acceptation at present is that of Cohnheim, wha 

 believes that it consists in some alteration in the tissues, which 

 begins in those forming the walls of the blood-vessels, or 

 immediately adjacent to them. This opinion is supported by 

 the observation of Eyneck,! that stasis may be noticed in 

 vessels where the blood has been washed out and replaced by 

 milk. The milk globules accumulate in the capillaries of the 

 irritated part in much the same way as the corpuscles usually 

 do. This would seem to show conclusively that it is the vessel, 

 and not the blood it contains, which obstructs circulation and 

 leads to stasis. Yet it is hard to see how the appearances 

 observed are to be explained thus, and they are exactly those 

 which we should expect from the blood suddenly becoming 

 thicker, and consequently flovving less easily. Both Henle and 

 Wharton Jones have adopted this view, the former supposing 

 that the blood became thicker, both by the plasma losing water 

 by exudation through the walls, and by having the proportion 



* Paget, Surgical I'athology, 1863, p. 227. Colmheiin, Neue Uidersuchungen. 

 •f Kyneck, Rolletfs Untersuchungen, 1870 p. 103. - ... 



