INFLAMMATION OP ARTERIES AND VEINS. 249 



tions of matter, forming pustular elevations of the intima. The 

 microscope tells us much more about the condition of a vessel 

 thus altered. Its entire wall is in a state of inflammatory pro- 

 liferation. Thousands of young elements, which may be sum- 

 marily termed pus-corpuscles, lie between the fibres of the 

 adventitia, between all the layers of the muscular coat, between 

 the striated lamellae of the intima. In the adventitia, besides 

 the cells, I have occasionally found larger aggregations of an 

 amorphous, jelly-like material, which I regard as coagulated 

 lymph ; here also, as well as in the outer layers of the muscular 

 coat, extravasations occur, which extend along the vessel for a 

 variable distance. It seldom happens that the pus-formation in 

 the external coat goes so far as to cause abscesses. When it 

 does, the abscesses are like long streaks of creamy pus following 

 the course of the vessel ; they must not be confounded with 

 vessels which may happen to be filled with softened thrombi. 

 The intima is less constantly involved in the morbid process ; 

 indeed I might almost say that in the majority of cases the 

 intima is less altered than either of the other coats. It depends 

 for its nutrition so much upon the blood which circulates in the 

 vessel, that the occurrence of coagulation at once cuts off its 

 chief source of pabulum, and leaves it a prey to necrosis, unless, 

 as in the organisation of thrombi, vessels are forthwith developed 

 in the coagulum. The passive behaviour of the intima must 

 therefore be attributed to its lack of vital energy and nutrient 

 material ; and this view is confirmed by the observation that the 

 farther progress of the mischief not unfrequently results in a true 

 necrosis of the intima and its detachment from the middle coat. 



§ 213. Apart from thrombotic arteritis and phlebitis there is 

 hardly such a thing as acute inflammation of the walls of vessels. 

 On the other hand, I must remind the reader that the vessels 

 are continuous by their adventitia with the general connective 

 tissue of the organs — that, rightly understood, the walls of the 

 vessels are really a part of that connective tissue, and are there- 

 fore capable of taking a most active share in all inflammations, 

 however acute, of the various organs in which they ramify. 

 Indeed we shall find that in many of the inflammatory disorders 

 of internal organs, e.g. of the pia mater, kidneys, &c., the chief 

 seat of the morbid changes is in the adventitia and the imme- 

 diate neighbourhood of the vessels. 



