318 SEROUS MEMBllAXES. 



fibrinous eftnsion. \\e may suppose a loud, grazing friction- 

 sound to liave been heard at first all over the affected region ; 

 this became limited to the upper part of the serous sac, while 

 tlie lower part w^as filled w^ith fluid. The extent of effusion 

 might have been determined by percussion. The pyrexia was 

 intense, and the patient succumbed wdien the disease w^as at its 

 height, partly to the fever, partly to the obstacles in the way of 

 the pulmonary or the cardiac movements. We lay open the 

 pleural sac or the pericardium, and we find it filled to a greater 

 or less extent wdtli a clear, straw- coloured fluid, in which are 

 suspended soft shreds and flakes of a yellowish-white colour. 

 The lining membrane is coated with a pale, yellow^ish or reddish, 

 transparent or opaque, coherent and elastic, or brittle and friable 

 substance, from which it is distinguished partly by its colour 

 and consistency, partly by the fact that this matter can be 

 stripped or peeled off' with varying degrees of facility. The aspect 

 and general arrangement of this substance gives us the notion 

 of a soft, plastic material having been introduced between the 

 layers of the serous sac and subsequently moulded by the move- 

 ments of the lungs or heart as the case may be. A portion of 

 it has accumulated at those points wdiere it is least in the w-ay of 

 the movements of the viscera ; it occupies all the chinks and 

 corners, it fills up the inflexion of the pleural sac betw^een the 

 diaphragm and the thoracic walls, it obliterates the cardiac 

 sulcus and the fold of pericardium which is reflected over the 

 great vessels. But wdiere the substance in question forms a 

 thick layer on the surface of the heart or lungs, it exhibits a 

 peculiar reticulated or villous aspect, such as might a prioii be 

 expected from a consideration of the alternate apposition and 

 separation of the visceral and parietal lamellae ; these appear- 

 ances may be exactly imitated by squeezing a layer of putty 

 between two plates of glass, and then tearing them apart. 



The ensemble of these characters indicates a close analogy 

 with coagulated fibrin ; and there has long been a tendency to 

 regard this material simply as fibrin exuded from the blood, and 

 to assume that it subsequently formed the adhesions. Various 

 protests against this assumption w^ere how^ever lodged at an early 

 period. Reinhardt in particular denied the possibility of pure 

 fibrin ever becoming organised, and was the first to describe 

 liow it underwent transformation into a fatty-mucous, opaque 



