The Relation of Autolysis to the Histological changes occurring in Necrotic Areas.

In I900 JacobyI found that if a portion of a dog's liver was ligated off and the dog kept alive for some time afterward, the necrotic isolated portion contained free leucin and tyrosin. This was the first actual demonstration that the retrogressive changes in areas of anemic* necrosis are associated with, and presumably the result of, enzymotic autolytic processes. Since that time it has been generally accepted that the softening and absorption of necrotic tissues is the result of autolysis by the proteolytic enzymes contained within the degenerated cells, and numerous chemical investigations have shown that in gangrenous tissues, suppurating areas, resolving exudates, degenerating tumors, and other similar conditions the products of proteid digestion may be found. There can be little question, therefore, that autolysis is an important factor in all processes associated with the removal of areas of degeneration, but as yet there has been little consideration of the relation of autolysis to the histological changes that occur in such areas, nor has it been determined to what extent the autolysis is accomplished by (I) the intracellular enzymes of the necrosed cells; (2) by the enzymes of invading leucocytes, and (3) by the constituents of the blood plasma. Neither do we know to what extent the action of these digestive agents is modified by various conditions and substances existing within the body. A few studies of the histological changes occurring in aseptically and antiseptically preserved pieces of organs kept for varying periods outside of the body have been made, but most of them antedate the general appreciation of the intracellular proteolytic enzymes. Meissner2 observed many years ago that aseptically preserved organs retained their general