436 RETROGRESSIVE CHANGES 



equally free from glycogen (two positive in 260 specimens), while it was 

 constant in teratomas, rhabdomyomas, hypernephromas, and chorio- 

 epitheliomas. Fifty and seven-tenths per cent, of the sarcomas and 

 43.6 per cent, of the carcinomas showed glycogen, most abundant in 

 squamous-cell epitheliomas; columnar-celled carcinomas contain gly- 

 cogen 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 pro- 

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

 Barfurth, nematodes in glycogen-free animals may contain glj'cogen. 

 The glycogen is found chiefly in the connective tissues of the intestinal 

 parasites, 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 eosinophile 

 granules are related to glycogen, we may have here an explanation 

 of the occurrence of eosinophilia in infection with animal parasites. 

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



Glycogen in Leucocytes. — The occurrence of glycogen in the 

 blood has aroused much interest, particularly in relation to its diag- 

 nostic value. Many 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- 

 morphonuclear neutrophiles, but seldom in large and small mononu- 

 clear cells and eosinophiles.' Occasional granules are also found free 

 (or perhaps contained in blood-platelets) in all blood, whether normal 

 or pathological. 2 Hirschberg^ states that normal animals of all 

 species have leucocytes giving an iodin reaction for glycogen if proper 

 technic is used, but which is not obtained by the ordinary iodin-gum 

 solution method unless the glycogen is rendered abnormally insolu- 

 ble by toxic injury; this is an explanation for the relationship of 

 iodophilia and infections. According to Wolff-Eisner the leucocytes 

 in myeloid leukemia contain no glycogen granules. It does not seem 

 to be settled whether the glycogen is taken on by the leucocytes at 

 the place of pathological lesion, or in the bone-marrow under the in- 

 fluence of circulating poisons, or both. Habershon states that from 

 1 to 16 per cent, of all leucocytes normally contain glycogen granules, 



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

 Arch, mikros. Anat., 1885 (25), 269; also liusch, Arch, internat. physiol., 1905 

 (3), 49; Brault and Loeper, Jour. Phys. et Path. Gen., 1904 (6), 295 and 720. 



1 See Bond, Brit. Med. Jour., Feb. 3, 1917. 



=^ Literature— Locke and Cabot, Jour. Med. Research, 1902 (7), 25; Locke, 

 Boston Med. and Surg. Jour., 1902 (147), 289; Reich. Bcitr. klin. Chir., 1904 (42), 

 277; Kiittner, Arch. klin. Chir., 1904 (73), 438; Gulland, Brit. Med. Jour., 1904 

 (i), 880; Habershon, Jour. Path, and Bact., 1900 (11), 95; Wolff, Zeit. klin. Med. 

 1904 (51), 407. 



3 Virchow's Arch., 1908 (194), 367. 



