Infarction. 145 



capillary supply sufficient for this purpose. Moreover it may hap- 

 pen that it is not one single artery that is blocked, but that at the 

 same time its anastomosing vessels are also occluded, under which 

 circumstances there necessarily result circulatory disturbances hav- 

 ing serious consequences. The area which is deprived of its blood 

 supply loses its blood color, and assumes a paler and drier appear- 

 ance than the surrounding tissue; the blood remaining in it be- 

 coming decolorized because its hccmoglobin is dissolved, disin- 

 tegrated or dispersed by diffusion, and the anaemic tissue, in which, 

 too, the lymph is stagnant and coagulates, undergoing regressive 

 metamorphoses. Such an ansmic and dead area is known as an 

 anccmic infarct. 



A tissue which is thus cut out of the circulation and 

 deprived of its arterial blood supply is not necessarily anaemic 

 but on the contrary may be the scat of a distinctly pathological 

 engorgement as a result of regurgitation of blood from the veins. 

 Particularly where the veins of the part whose arterial supply 

 has been occluded anastornose with adjacent veins, the blood, which 

 in the latter vessels is under a certain amount of pressure, flows 

 over into the former and back into the anaemic network of capil- 

 laries ; just as the water from a brook moves back into the side 

 ditches of a stream if these have no fall. There is no force from 

 the arteries in such a site capable of driving the blood through the 

 afifected area and the capillaries in which the venous blood collects 

 become distended and their walls flaccid and permeable from the 

 lack of normal bathing with flowing blood. The venous blood 

 thus stagnating in the capillaries partly leaks through their w^alls, 

 partly undergoes coagulation; and the whole area thus engorged 

 with blood assumes a dark red hue. Such an area is spoken of as 

 a hccmorrhagic infarct (infarcire, to stop up). [Others would 

 refuse the importance attached by the author to the above idea of 

 a venous regurgitation giving rise to the engorgement of the in- 

 farcted area with blood. Anastomotic communications are usu- 

 ally more numerous and free between veins than between arteries ; 

 and if this be true and the author's views correct, anremic infarcts 

 should be the exception rather than of as common occurrence as 

 they actually appear. If venous reflux were as easy as supposed 

 by the older adherents of this theory, anaemic infarcts should be 

 practically unknown. From the editor's viewpoint the process is 

 more easily understood if we accept the belief, which seems rea- 

 sonable, that there are no true end-arteries and that there are al- 



