250 CIECrLATOEY APPARATUS. 



(^, Chronic InJiammatioJi, 



§ 214. Chronic inflammatory changes may occur in every 

 part of the vascular system ; but they are nowhere so im- 

 portant as in the internal coat of the arteries, where they give 

 rise to the endoarteritis chronica deformans of Virchow. Tlie view 

 that this disorder (also known as atheroma) is of an inflamma- 

 tory character, is by no means of recent date. A peculiarly 

 transparent material which projects above the level of the intima, 

 and which, as will presently be seen, is nothing more than the 

 altered intima itself, used to be regarded as an inflammatory 

 exudation, and the entire process was accordingly viewed as an 

 exudative inflammation. An obvious objection to this view is 

 that the exudation, in its quality of liquor sanguinis, had no 

 occasion to coagulate at the very moment when it was reunited 

 with its parent fluid. Accordingly, RoJdtansJd started the theory 

 that the substance in question, though really coagulated fibrin, 

 had not exuded from the vasa vasorum, but had been precipi- 

 tated at the inflamed point of the vascular wall (where it formed 

 a deposit), from the blood-current itself. This position likewise 

 came ultimately to be untenable. Lobsteiuj and after him Virchoiv, 

 taught us to look for the essential part of tlie process in an altera- 

 tion of the proper tissue of the intima, and to eliminate what- 

 ever substances might afterwards have been deposited at the 

 seat of mischief from the blood. Virchow laid the foundations 

 of our present theory concerning the morbid change in question. 



§ 215. It consists in a chronic inflammation of the inner 

 coat of the vessel. True, we cannot detect all the cardinal symp- 

 toms of inflammation, but only swelling and perhaps impairment 

 of function ; but the finer alterations which the intima midergoes 

 are throughout analogous to those which occur in connective 

 tissue under the influence of prolonged irritation. There are 

 many grounds for thinking that a mechanical irritation of the 

 vascular wall may be at least one of the causes to which the 

 morbid changes are due. For these are chiefly found at such 

 points as are exposed to the fiill stress and impact of the blood ; 

 <^.g. the upper curvature of the aortic arch, the points of origin 

 and bifurcation of the vessels. Still, mechanical irritation must 

 not be regarded as the sole cause of the disorder, though it 

 determines its localisation. Among other predisposing causes are 

 advanced age and free living, especially a free use of alcoholic 



