|| Checking for direct PDF access through Ovid
People have used the words inflammation and fever for millennia, but the meaning of inflammation has gradually changed whereas that of fever has remained reasonably constant. Whereas inflammation originally referred to the combination of heat, redness, swelling and pain in a local area, it has gradually evolved to focus upon cellular and humoral processes that occur in tissues when external or internal agents cause damage to them. The classical manifestations are no longer obligatory. Diseases that affect internal organs such as the kidneys are nowadays commonly described as inflammatory despite entirely lacking those classical manifestations, but possessing evidence of cellular proliferation and/or involvement of factors such as cytokines. These conceptual changes have resulted from the application of progressively improved investigational techniques such as microscopy, thermometry, experimental pathology, and tissue culture. The consequence of them has been largely to extinguish the fire that previously epitomised inflammation.