Inflammation. Phlogosis. Phlegmasia. 51 



however, serves to distinguish it from the liquid of mechanical 

 dropsy, as does also the greater quantity of cells and nuclei, of 

 common salt and phosphates. It is usually straw colored in 

 mass, but is sometimes slightly opalescent by reason of the num- 

 bers of cells and floating filaments of fibrine. Serous exudations 

 take place in the early stages of inflammations (as in catarrh) and 

 in inflammations of serous membranes (pleura, peritoneum, 

 joints), in strong, vigorous subjects. They constitute the liquid 

 contents of blisters whether raised by medicinal irritants, chafing, 

 or heat. They clot under heat and nitric acid with a firmness 

 proportionate to the amount of albumen. 



These effusions are dangerous by reason of their interference 

 with the functions of organs by pressure as with the dilatation of 

 the lungs, the movements of the heart, the action of joints, or the 

 integrity of the brain or spinal cord. "When the causative disease 

 has subsided they are usually speedily reabsorbed, the cells pas- 

 sing into the lymph vessels, or becoming degenerated, liquefied, 

 and absorbed. Yet serous effusions often remain as permanent ac- 

 cumulations. For the blood staining of serous effusions and their 

 clearing up, see under pleurisy. 



Fibrinous Exudate. This is characterized by the amount of 

 fibrinogen and fibro-plastin in its composition and by the compar- 

 ative absence of leucocytes. It oozes through the vessels and co- 

 agulates in the tissues or on the surface of inflamed serous or mu- 

 cous membranes. The more liquid part separating from the co- 

 agulum escapes from the free surface or accumulates in the lower 

 part of the serous cavity. The coagulation is doubtless caused 

 by the fibrine ferment derived from the rapidly proliferating cells 

 and degenerating leucocytes. It usually occurs promptly in or 

 on an inflamed tissue, but in contact with healthy structures only 

 (as in a serous sac) it may remain fluid for an indefinite length 

 of time. This exudate constitutes the false membranes that form 

 on the pleura, pericardium or arachnoid, the coagulum of fibrin- 

 ous pneumonia, and the plastic lymph on the surface of a granu- 

 lating wound. It is especially injurious by reason of its envelop- 

 ing organs (lungs, heart, bowels, iris) and subjecting to perma- 

 nent compression by reason of its contracting, also by binding 

 them to adjacent structures by false membranes. In coagulating 

 it becomes first fibrillar then granular and finally undergoes mo- 



