The above-mentioned characters, especially the opacity and the greenish coloration, are here more strongly developed. It consists, together with an amorphous blastema, of nucleus and cell-formations, more or less akin to pus-nuclei and pus-cells, and of a predominating quantity of granulated substance. It adheres loosely to the exudation-surfaces and deliquesces rapidly. It answers to fibrin 4.

These exudates occur most of all upon membranous expansions, upon mucous membranes (as the well-known croup), upon serous and synovial membranes, and in the substance of the lung. Again, they occur in areolar tissue, in the pia mater, in the convexity of the cerebral hemispheres, upon the endocardium and the internal bloodvessel membranes, in parenchymata, and upon the surface of both internal and external sores. Almost all the pneumoniae, except those ending in slow resorption or induration of their product, belong to this class, and pre-eminently those in which the lung becomes enormously distended with a very copious, rapidly deliquescent yellow effusion, the stage of red hepatization being, in Hodgkin's opinion, here altogether wanting.

As the exudates break down, they exert, especially after long-continued contact, the aforesaid corrosive liquefying influence upon their substrata, occasioning ulcerous loss of substance, pulmonary abscess, destruction of serous membranes, ulcerous perforation of the thoracic, the abdominal, parietes, etc.