434 RETROGRESSIVE CHANGES 



standing next, and it is also present in squamous epithelium (particularly the mid- 

 dle layers), especially that of the vagina (Wiegmann), but not in slightly stratified 

 (cornea), transitional, or cylindrical epithelium. Normal human kidneys do not 

 seem to show glycogen, but it may be present in the kidneys of mice, rabbits, and 

 cats. There is considerable in the heart muscle.*^ The amount in different skele- 

 tal muscles varies,^^ usually being especially abundant in the diaphragm. Gly- 

 cogen is most abundant in the uterus at the time of child-birth, and is abundant in 

 the placenta; but it is also present in the uterus and tubes independent of preg- 

 nancy.^" After pancreas extirpation, Fichera^^ observed a disappearance of all 

 visible glycogen, except a little in the cartilage and stratified epitheliuni ; hence he 

 considers the glycogen-content as a function of cell nourishment. Fat and gly- 

 cogen often occur together, although one may be present without the other (Gierke). 

 Presumably the failure to find glycogen in certain cells depends rather on a 

 failure of technic than on a total absence of glycogen. 



There has been some diversity of opinion as to whether glycogen occurs as 

 granules in the living cell, or whether the granules are formed from a homogeneous 

 substance by hardening fluids. In view of the clear-cut, definite spaces it may 

 leave in cells when dissolved out, glycogen probably occurs as granules, especially 

 when present in abnormally large quantities. Ervin^^ believes that glycogen, like 

 fat, may exist within the cells so finely divided that it cannot be stained bj'' glycogen 

 stains. The studies of Arnold have shown that in many cells the glycogen takes on 

 a definite structure in close relation to the plasmosomes. It has been suggested 

 that the intra-epithelial hyaline bodies (Russell's fuchsin bodies) are glycogen, 

 which idea is probably not correct. Habershon and others have suggested that 

 eosinophile granules are either glycogen or related to it. The presence of glycogen 

 in the cells seems to cause no injury to the cytoplasm, and if it again disappears, 

 the cells become quite normal. ^^ Even the nuclei may contain granules of 

 glycogen without evident permanent injury. 



Pathological Occurrence 



According to the results obtained by Fichera and Gierke, it seems 

 probable that glycogen accumulation is produced under the same 

 conditions as are fatty changes, i. e., when oxidation is locall}^ or 

 generally impaired. Fat and glycogen are, therefore, often found 

 together in the margins of infarcts and of tubercles, in passive con- 

 gestion of the liver, and in heart muscle with fatty changes due to 

 severe anemia. The glycogen, being more labile, seems to disappear 

 early when the cells become necrotic, and hence glycogen is not pres- 

 ent in older necrotic areas where the fat still persists. (This proba- 

 bly accounts for the frequently repeated statement that glycogen and 

 fat do not occur together.) Ervin^- believes that glycogen is impor- 

 tant in holding intracellular fats emulsionized, and hence in its ab- 

 sence in diabetes the fats become visible as fatty degeneration — hence 

 the inverse ratio of glycogen and fat. Whether the glycogen can be 

 transformed into fat, perhaps forming an intermediary stage in a trans- 

 formation of protein into fat, has not been determined, but there 



88 Berblinger, Ziegler's Beitr., 1912 (53), 155. 

 8M.ipska-Mlodowski, Beitr. path. Anat., 1917 (64), 18. 



90 McAllister, Jour. Obs. Gyn. Brit. Emp., 1913 (34), 91. 



91 Ziegler's Beitr., 1904 (30), 273, literature. 



92 Jour. Lab. Chn. Med., 1919 (5), 14(). 



''Yet Teissier (Compt. Rend. Soc. Biol., 1900 (52), 790) believes the amount 

 normally present in the liver is strongly bactericidal, and in a later publication 

 (ibid., 1902 (54), 1098) considers that it is toxic to liver-cells. ^^Vndelstadt 

 (Cent. f. Bact., Abt. 1, 1903 (34), 831) found that under certain conditions gly- 

 cogen impedes hoinoly.sis by normal serum. • 



