INFLAMMATION. 123 



of exudative inflammation those in which the extravasated serous fluid 

 is the most marked feature are often named serous inflammations. If 

 tibriii predominate, it is called flbrinous ; if associated with much blood 

 extravasation, it is termed hcemorrhagic. When the agencies are present 

 which induce the necessary vascular changes and promote the emigration 

 and gathering, and often the destruction, of leucocytes in considerable or 

 large numbers, we have a suppurative or purulent inflammation. If much 

 tissue death be associated with the process, it is named necrotic inflam- 

 mation. 



Again, if certain mucous membranes or mucous glands be subjected 

 to the inciting agencies, they may respond by an overproduction of 

 mucus as well as by an increase or death of cells; this is mucous or 

 catarrhal inflammation. Finally, these various forms of exudate may be 

 produced simultaneously, whence arise such compound designations as 

 M>-o-purulent, muco-purulent, etc., inflammation. Inflammation with the 

 formation of new tissue is called productive or reparative. 



Local inflammation, especially when incited by micro-organisms, is 

 often associated with systemic infection due to a distribution of the in- 

 citing agents through the body. This condition will be considered in the 

 chapter dealing with the Infectious Diseases (see page 202). 



It has seemed wise to many to attempt to draw a sharp distinction 

 between those phases of inflammation which involve only the degener- 

 ation of tissues or the redistribution of already formed tissue elements 

 scrum, fibrin, and blood and those phases which are productive or 

 reparative. But while this attempt aims at the recognition of a biologi- 

 cal distinction of fundamental importance, it encounters the great prac- 

 tical difficulty that both phases of the reaction of tissues to injury, the 

 exudative and the productive, occur together, so that none of the named 

 classes of inflammation represent simple and unmixed forms of tissue 

 reaction. The important thing is to conceive, as clearly as our knowl- 

 edge permits, the nature of the processes which underlie these various 

 manifestations of disturbed cell function and their associated tissue 

 alterations. Then the names may serve useful temporary ends at le"ast, 

 without implying too much or concealing too little knowledge. 



Survey of the Inflammatory Process and its Significance. 



If now, from the vantage-ground which we have won by our survey 

 of various typical phases of inflammation, we seek to gain an insight into 

 the forces which dominate the varied processes, we note at once tliat 

 from first to last the cell and tissue performances in inflammation, how- 

 ever exaggerated or perverted, are only the expression of physiological 

 capacities which belong to the structures involved. Thus the contrac- 

 tions and dilatations of the vessels are paralleled in health. The exuding 

 of fluids through their walls occurs by processes akin to those by which 

 blood pressure, osmosis, and selective filtration in eudothelial cells main- 

 tain the initial circulation into and through the tissue spaces. Emigra- 



