ATROPHY, DEGENERATION, PIGMENTATION, AND NECROSIS. 



GLYCOGEN INFILTRATION. 



Glycogen appears under abnormal conditions in the cells as hyalin, 

 mostly globular masses of varying size (Fig. 20). It is soluble in water, 



is stained brownish-red by iodine, and 

 does not assume a greenish color by the 

 further addition of sulphuric acid. In 

 diabetes it may occur in large quantities 

 in the liver cells and in the epithelial 

 cells of the uriniferous tubules, especially 

 in those of Henle's loop (Fig. 331) and 

 in leucocytes. It may be found in fresh 

 pus cells, in the cells of various forms of 

 tumors, and in leucocytes in the blood in 

 leukaemia, in chronic diseases of the 

 gastro- intestinal tract in children, and in various chronic diseases. 



TECHNIQUE. If the tissue to be examined for glycogen be fresh, the iodine should 

 be used in solution in glycerin (equal parts of Lugol's solution and glycerin), in order 

 to avoid its solution. If specimens are to be hardened, this should be done in absolute 

 alcohol to avoid the solution of the glycogen. Sections may be stained with picro-acid 

 fuchsin (Van Gieson's stain) or with a dilute solution of iodine in alcohol (tincture 

 iodine 1 part, absolute alcohol 4 parts), cleared up and studied in oil of origanum. 



FIG. 20. GLYCOGEN INFILTRATION EPI- 

 THELIUM OF KIDNEY. 

 The glycogen droplets are unstained. 



SEROUS INFILTRATION OF CELLS (Hydropic Degeneration, 

 Vacuolization). 



Under many pathological conditions, cells, especially those of mucous 

 membranes, glands, muscles, tumors, etc., contain one or more larger or 

 smaller droplets of clear fluid (Fig. 21). The cell may thus be distended. 



FIG. 21. SEROUS INFILTRATION 

 OF EPITHELIAL CELLS. 



FIG. 22. Mucous DEGENERATION OF EPITHELIAL 



CELLS. 

 From a cyst-adenoma of the ovary. 



These droplets are usually extra-nuclear and may crowd the nucleus to 

 one side of the cell. The nature and source of this accumulated fluid are 

 not known. Its transparent appearance in the granular protoplasm has 

 given rise to the term "vacuole." It maybe associated with general 

 tissue oadema, with inflammatory and degenerative processes, etc. 



