PRINCIPLES OF VETERINARY SURGERY 19 



3. Oscillation. — Contents of the vessels cease to move, 

 and sway back and forth. 



4. Stasis.— There is nov(^ no movement of any kind; 

 thjombosis may occur. 



5. Emigration. — The leucocytes w^ork their way through 

 the vessel wall, by means of their active amoeboid processes. 

 Red cells in fewer numbers escape through spaces between 

 the endothelial cells of the capillaries. 



6. Exudation. — Owing to the increased permeability of 

 the vessel wall, variable quantities of the serous fluids escape ; 

 later a plasma-like fluid may accumulate, and fibrin may be 

 precipitated. The greater the damage to the vessels the 

 more nearly the exudation approximates that of the blood, 

 and the greater the number of corpuscles it contains. 



The emigrated cells and exuded fluids at once begin their 

 work of repair. Both red and white corpuscles at first re- 

 main near the vessels from which they have escaped, but 

 they are soon pushed away by other corpuscles or washed 

 on by the escaping fluid. The white corpuscles have in addi- 

 tion their own peculiar power of locomotion, stimulated and 

 directed by the irritating substance which caused the injury 

 to the tissue. Hence ultimately, they may be found far from 

 their point of egress from the vessels. The leucocytes and 

 also certain fixed tissue cells take up into their own bodies 

 whatever foreign substances they find in the area of irrita- 

 tion. In this way the bacteria, chemical irritants and tissue 

 debris are disposed of while the exuded fluids aid in washing 

 all away into the lymphatics. Any unremoved blood-cor- 

 puscles or fibrin later undergo fatty degeneration, and thus 

 complete removal of the irritating products is eventually 

 brought about. 



The tissue cells which have been destroyed are replaced 

 by multiplication of the surviving cells, epithelium by epi- 

 thelium, muscle by muscle, nerve by nerve, etc. The stasis 



