432 RETROGRESSIVE CHAXGES 



roborate neitlier of these ideas, and considers that gl3^cogen appears in 

 tumors under exactly the same conditions in which it appears in other 

 tissues; i. e., when cell nutrition and oxidation are impaired. Ap- 

 parently, however, hoth the emhryonic origin and local retrogressive 

 changes determine the deposition of glycogen in tumors. Glycogen 

 is particularly abundant in squamous epithelium of epitheliomas that 

 have gone on to homification ; ^'^ in testicular tumors, hyperneph- 

 romas, parathyroid tumors (Langhans),*" endotheliomas, chondromas, 

 and myomas, and it also occurs in the connective tissues surrounding 

 tumors. Of 1544 tumors of all sorts examined by Lubarsch,^^ 447 

 (or 29 per cent.) contained glycogen microscopically; fibromas, oste- 

 omas, gliomas, hemangiomas were always free from glycogen; and 

 lipomas and lymphangiomas nearly always. Adenomas are almost 

 equally free from glycogen (two positive in 260 specimens), 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 carcinomas show glycogen, most abun- 

 dant in squamous-cell epitheliomas ; columnar-celled carcinomas con- 

 tain 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.'*- It has been found in protozoa, as 

 well as in all varieties of intestinal worms. According to Barfurth, 

 nematodes in glycogen-free animals may contain glycogen. The gly- 

 cogen is found chiefly in the connective tissues of the intestinal para- 

 sites, but in some of the nematodes it occurs chiefly in the sexual 

 organs and muscle-cells. The walls of the hydatid cysts contain much 

 glycogen, which is, perhaps, related to the usual presence of sugar 

 in their contents. If Habershon's contention is correct, that eosino- 

 phile granules are related to glycogen, we may have here an expla- 

 nation of the occurrence of eosinophilia in infection with animal para- 

 sites. (See also "Animal Parasites," Chap, v.) 



Glycogen in Leucocytes. — The occurrence of glycogen in the blood 

 has aroused nuicli interest, particularly in relation to its diagnostic 

 value. INIany leucocytes contain granules that stain with iodin, and 

 although it is possible that these are not all granules of glycogen, 

 yet, for the most part, they probably represent this substance in 

 excessive quantities. The granules are observed chiefly in the poly- 

 morphoinicloar neutrophiles, but also in large and small mononuclear 

 cells and cosinophiles. Occasional granules arc also found free (or 



■''!> Tn mouse tvimora TTaaland found fflycofren only in squamous coll caroinoma, 

 and in the connective tissue aurroundinfr other tumors (Jour. Path, and Tiact., 

 H»OH (12). 4.3!)). 



40Virchow's Arch., 1007 flSn), 1:58. 



41 Virchow's Arch., 1900 (183). 188. 



•*- Elaborate treatise on occurrence of <rlyco<ren in lower aniinals by I'arfurth, 

 Arch, niikros. .Xnat., 1885 (2.5). 200; also r>usch. Arch, internat. phvsiol.. 1005 

 (3), 49; Brault and Loeper, Jour. Phys. et Path. G(n\., 1004 (6), 205 and 720. 



