GLYCOGEN IN PATHOLOGICAL PROCESSES 361 



from outside the cell, and not formed directly from degener- 

 ated proteid. It seems to be deposited only in cells that are 

 still living, although it can become split up in dead cells. All 

 cells, but especially muscle-cells and leucocytes, seem able to 

 lay up glycogen in visible amounts under certain conditions. 

 In inflamed areas glycogen is found both in tissue-cells and 

 leucocytes, but not in cells showing nuclear degeneration (Best, 

 Gierke). In pneumonia the leucocytes of the exudate, and to 

 a less extent the alveolar epithelium, contain glycogen as well 

 as fat. 



Glycogen in Tumors. Glycogen has been observed fre- 

 quently in tumors. Brault believed the quantity an index of 

 rate of growth, on the principle that glycogen appears most 

 abundantly in embryonal tissues, and therefore in tumors the 

 amount of glycogen should agree with the degree to which the 

 cells have gone back to the embryonic type. Lubarsch consid- 

 ered that only tissues normally containing glycogen give rise to 

 glycogen-containing tumors. Gierke could corroborate neither of 

 these ideas, and considers that glycogen arises in tumors under 

 exactly the same conditions in which it arises in other tissues ; 

 i. e.j when cell nutrition and oxidation are impaired. Apparently, 

 however, both the embryonic origin and local retrogressive changes 

 determine the deposition of glycogen in tumors. Glycogen is par- 

 ticularly abundant in squamous epithelium of epitheliomas that 

 have gone on to hornification ; in testicular tumors, hyperneph- 

 romas, endotheliomas, choudromas, and myomas, and it also 

 occurs in the connective tissues surrounding tumors. Of 1544 

 tumors of all sorts examined by Lubarsch, 1 447 (or 29 per 

 cent.) contained glycogen microscopically ; fibromas, osteomas, 

 gliomas, hemangiomas were always free from glycogen ; and 

 lipomas and lymphangiomas nearly always. Adenomas are 

 almost equally free from glycogen (two positive in 260 speci- 

 mens), while it was constant in teratomas, rhabdomyomas, 

 hypernephromas, and chorioepitheliomas. Fifty and seven- 

 tenths per cent, of the sarcomas and 43.6 per cent, of the carci- 

 nomas show glycogen, most abundant in squamous-cell epitheli- 

 omas ; columnar-celled carcinomas contain glycogen much less 

 often, and it is always absent in " colloid cancers." 



Animal parasites, in common with other invertebrates, 

 usually show abundant quantities of glycogen. 2 It has been 



1 Virchow's Arch., 1906 (183), 188. 



2 Elaborate treatise on occurrence of glycogen in lower animals by Barfurth, 

 Arch, mikros. Anat, 1885 (25), 269; also Busch, Arch, internal, physiol., 

 1905 (3), 49; Brault and Loeper, Jour. Phys. et Path. Gen., 1904 (6), 295 

 and 720. 



