610 [June 11, 



briefly to inflammation, the most important of all pathological 

 conditions. 



If we inquire what is the great peculiarity of inflamed parts in 

 relation to the blood as examined by the naked eye, we see that it 

 consists in a tendency to induce coagulation in their vicinity im- 

 plying, according to the conclusions just stated, that the affected 

 tissues have lost for the time being their vital properties, and com- 

 port themselves like ordinary solids. Thus, when an artery or vein 

 is inflamed, coagulation occurs upon its interior, in spite of the cur- 

 rent of blood, precisely as would take place if it had been artificially 

 deprived of its vital properties. On one occasion I simulated the 

 characteristic adherent clot of Phlebitis by treating the jugular vein 

 of a living sheep with caustic ammonia, and then allowing the circu- 

 lation to go on through the vessel for a while, when, on slitting it 

 up, I found its lining membrane studded with grains of pink fibrin 

 which could be detached only by scraping firmly with the edge of a 

 knife. Again, comparing an inflammatory exudation into the peri- 

 cardium or into the interstices of the cellular tissue with dropsical 

 effusions into the same situations, we are struck with the fact that, 

 while the liquor sanguinis effused in dropsy remains fluid, the inflam- 

 matory product coagulates. Now we know that in intense inflam- 

 mation the capillaries are choked more or less with accumulated 

 blood- corpuscles, which must cause great increase in the pressure of 

 the blood upon their walls ; and from what we know of the effect of 

 venous obstruction in causing dropsical effusion of liquor sanguinis 

 through increased pressure, we are sure that we have in the inflam- 

 matory state the physical conditions for a similar transudation of fluid 

 through the walls of the capillaries. And the natural interpretation 

 of the difference in the two cases as regards coagulation seems to be, 

 that whereas in dropsy the fluid is forced through the pores of 

 healthy vessels, in inflammation the capillary parietes have lost their 

 healthy condition, and act like ordinary matter ; so that the liquor 

 sanguinis, having been subjected, immediately before effusion, to the 

 combined influence of the injured tissue and the blood- corpuscles, 

 has acquired a disposition to coagulate, just like the buffy coat of 

 horses' blood shed into a glass, or like the frog's liquor sanguinis 

 filtered by Miiller from its corpuscles, the injured vessels acting upon 

 the blood like the filter. 



