EESOLUTION. 29 



floating in the liquid, and often forming bands of adhesion 

 between the opposing surfaces of the inflamed membrane. 



In every instance of undoubted pleuritis, effusion of serum 

 takes place; and it is ridiculous to hear some speak of the 

 differences that are observable in the symptoms when this occurs, 

 and of the great danger to be apprehended. The effusion is part 

 and parcel of the process of inflammation from almost the outset, 

 and the only danger is owing either to the constitution of the 

 animal being bad, or the treatment irrational, or the attack of 

 more than ordinary severity, that the effusion may become 

 excessive, and cause death by suffocation. 



Serous effusion is sometimes the result of mechanical con- 

 gestion, as witnessed in oedema of the extremities, in ascites, 

 from disease of the liver, spleen, or heart, but this is totally 

 unconnected with inflammation ; in such instances the fluid is 

 clear, and generally contains but little fibrine, or any substance 

 that coagulates upon exposure to the air. 



The formation of a non -coagulating eff"usion in the various 

 cavities is very propitious; for so long as it remains liquid, 

 absorption may still ensue without its undergoing any ulterior 

 changes when the inflammation subsides. The subsidence of 

 the inflammatory action, however, is necessary, for, from what 

 has been already said, there is impairment of function, and 

 absorption does not readily take place. 



It has been shown by Beale, Simon, and others, that there 

 are two essential characteristics of inflammatory effusion : — 

 Ist. It contains certain ingredients in larger proportion than that 

 in which they exist in the blood — excess of chloride of sodium, 

 of phosphates, and albumen ; and 2d., organic germs find in it a 

 suitable place for growth. 



BLOOD EFFUSION, OR EXTBAVASATION". 



Tliis occurs chiefly from rupture of new blood-vessels de- 

 veloped in the newly-formed material which has just become 

 vascular. — (Eokitansky.) But we find it when there has been 

 no time for the formation of such new vessels, namely, at the 

 very commencement of an acute inflammation of the substance 

 of the lungs ; but this is rare, and betokens either a very bad 

 constitution, or that the inflammation is due to a very malignant 



