294 HISTOLOGY OF THE MORBID PROCESSES. 



the living body, as is the case in necrosis, those changes in structure 

 are more diverse and more marked than those incident to spontaneous 

 death resulting from removal. This has led to the distinction of 

 several varieties of necrosis, characterized by different structural 

 changes in the dead tissue, which are dependent upon the conditions 

 obtaining in the tissue at the time of death or after death has taken 

 place. 



Among the most striking changes incident to necrosis are those 

 affecting the nucleus. This may retain its form in great measure, 

 but lose its affinity for the nuclear dyes (" chromolysis," Fig. 262), 

 or the chromoplasmic substances may retain that affinity, but be 

 broken up into fragments, thus destroying the form of the nucleus 

 (" karyolysis," Figs. 260 and 261). Both of these changes are 

 indicative of the death of the nucleus and assure the death of 

 all parts of the cell. 



FIG. 260. FIG. 261. FIG. 262. 



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, * .* * 1.V '&"' * 1 ! *.'- 



&*4WO /'. 



f^v -''''* :< 5^A' ! ' '. '*-''"* 3 <*** * '* * 



__, k -% ,'fr-T^?^ 1 ': -* / * i * 



! 



?.- 



5k 



Changes in the nuclei of renal epithelial cells incident to necrosis. (Schmaus.) 

 Fig. 260. Destruction of the chromatic reticulum and condensation of the chromatin in 



masses of various sizes ; early stage of karyolysis. Nuclear membrane nearly gone. 

 Fig. 261. More advanced stage of nuclear destruction. The nuclear fragments lie free in the 



cytoplasm ; later stage of karyolysis. 



Fig. 262. Disintegration and disappearance of the chromatin without a coincident disinte- 

 gration of the form of the nucleus-chromolysis. 



1. Coagulation-necrosis. When the tissues that have suffered 

 death liberate fibrinoplastic substances and fibrin-ferment these 

 interact with the fibrinogen in the lymph and occasion a coagula- 

 tion of the necrosed tissue analogous to the production of fibrin. 

 These coagulated materials may appear as fine granules or as 

 hyaline masses of a dense, glassy character. This form of necrosis 

 is illustrated in the formation of the " membrane " in diphtheria, 

 which is the superficial portion of the affected part that has under- 



