358 RETROGRESSIVE PROCESSES 



for two to four months, showed absolutely no deleterious effects, 

 either locally or constitutionally. 1 Some of the French authors 2 

 claim that mucin possesses a slight bactericidal power. On the 

 other hand, Rettger 3 and others have found an apparently 

 typical mucin produced by certain varieties of bacteria. 



GLYCOGEN IN PATHOLOGICAL PROCESSES 



It seems probable that all, or nearly all, cells contain larger 

 or smaller quantities of glycogen, but it may be insufficient in 

 amount to be detected either microscopically or chemically. 

 Glycogen seems to be formed within the cells from the sugar 

 of the blood, through a process of dehydration and polymeri- 

 zation, and to be reconverted whenever necessary into sugar, by 

 a reverse process of hydrolysis. It is quite possible that both of 

 these processes represent merely the reversible action of an intra- 

 cellular enzyme, but this has not been established. We do 

 know, however, that soon after death the intracellular glycogen 

 is rapidly converted into dextrose. 4 



Properties of Glycogen. Glycogen is frequently called an ''animal 

 starch," having the same general composition as the starches (C 6 H 10 5 ) X , 

 and apparently, like the starches, it represents a relatively insoluble rest- 

 ing stage of sugar in the course of metabolism, It is readily soluble in 

 water, forming an opalescent, colloidal solution, and, therefore, has no 

 effect on osmotic pressure, and it is not diffusible. 5 Because of its solu- 

 bility and the rapidity with which postmortem change to dextrose 

 occurs, specimens that are to be examined microscopically for glycogen 

 must be hardened while very fresh in strong alcohol, in which glycogen is 

 insoluble. 6 One of the most characteristic reactions is the port-wine color 

 given by glycogen when treated with iodin ; this reaction may be applied 

 microscopically, solution of the glycogen being avoided by having the 

 iodin dissolved in a solution of gum arabic or in glycerin. Salivary 

 ptyalin rapidly converts glycogen into glucose, and this reaction may 

 also be used microscopically to prove that suspected granules are 

 glycogen. 



1 Levin (Med. Record, 1900 (57), 184) claims that mucin injected into thy- 

 roidectomized rabbits is very poisonous for them, while not harming normal 

 rabbits. 



2 Arloing, Compt. Rend. Soc. Biol., 1902 (54), 306, and 1901 (53), 1117. 



3 Jour. Med. Research, 1903 (10), 101. 



4 Literature concerning physiology of glycogen by Pfliiger, Pfliiger's Arch., 

 1903 (96), 398; and Cremer, Ergeb. der Physiol., 1902 (1, Abt. 1), 803. 



5 See Gatin-Gruzewska, Pfliiger's Arch., 1904 (103), 282. 



6 According to Helman (Cent. f. inn. Med., 1902 (23), 1017), glycogen may 

 be found in specimens preserved in alcohol as long as fifteen years. 



