HISTORY OF THE INFLAMMATORY PROCESS. 117 



bacteria. In these, as, for example, in the above-mentioned 

 septicaemia of the frog, where the vessels were directly 

 irritated by numerous bacilli, we find no visible extravasa- 

 tion. The wliite corpuscles, without leaving the vessel, attach 

 themselves to the bacteria in the blood, and endeavour to sur- 

 round them. And, in cases of intermittent fevers incredible 

 numbers of Spirillum appear in the blood, and remain for 

 several days " apparently without the slightest injury either to 

 the circulation of the blood itself or to the heart and vessels,"^ 

 a fact which certainly supports my theory rather than that 

 generally accepted. Again, it is well known that a blood clot, 

 lying outside a vessel, causes an inflammatory exudation — that 

 is, an accumulation of phagocytes — while a simple thrombus, 

 which is in direct contact with the wall of a vessel, will cause 

 no exudation ; probably because there are sufficient numbers of 

 phagocytes in the blood itself. From this point of view, the 

 struggle between irritant bodies and white corpuscles, when it 

 takes place directly in the vessels, may be spoken of as a kind 

 of hsemitis. 



' Coliuheini, ' Vorles. ueb. allgemeiue Pathologic,' 2 Auflage, Bd. 1, 1882, 

 p. 475. 



