VIIL 

 INFLAMMATION. 



Definition. — Inflamuialion may Le defined as the succession 

 of changes which takes ])hice in a living tissue as the result of 

 some kind of injury, provided that this injury be insufficient, 

 immediately, to destroy its vitality. — Scmderson. 



The process of inflammation is essentially the same in warm 

 and cold blooded animals, and by microscopial examinations it 

 has been proven to be the same in man. The process of inflam- 

 mation comprises changes in the blood vessels and circulation, 

 exudation of fluid and of l)lood corpuscles from the vessels, and 

 changes in the inflamed tissues. These changes all go on to- 

 gether. Inflammation causes a dilation of the arteries, which 

 gradually extends to the veins and capillaries. It affects arteries 

 chiefly, then the veins, and the capillaries but slightly. The 

 enlargement of the blood vessels is associated at the commence- 

 ment of the process with an acceleration in the flow of blood, and 

 is followed by a considerable retardation in the circulation, the 

 vessel still remaining dilated. As the stream gets slower white 

 corpuscles are seen in increasing numbers in the plasmatic layer 

 in the smaller veins, rolling slowly along, sticking here and 

 there, and finally coming to a standstill, until the vessels are 

 lined with them. This narrowing of the veins by layers of white 

 corpuscles, among which there are no red corpuscles, increases 

 the obstruction to the circulation, which becomes slower and 

 slower until all onward movements cease in the capillaries. 

 Finally, thrombosis or coagulation may take place, but not until 

 the capillary walls are dead. 



There is an escape of fluid and of blood corpuscles from the 

 vessels. The leucocytes immediately adjacent to the wall gradu- 

 ally sink into it and pass through into the surrounding tissues. 



(139) 



