GLICK 



141 



GLYCOGEN 



Glick, see Linderstr0m-Lang, Kaj, u., and 

 Holter, Heinz, Histochemical Advan- 

 ces. 



Glomus. Aortic and carotid, see Aortic 

 Paraganglion. 



Glucose Agar, see Bacteria Media. 



Glutathione. Demonstrated by Nitro- 

 prusside Reaction. Inhibiting factor 

 in Vitamin C silver test. 



Glycerides, see Neutral Fats. 



Glycerine. Much used in histological tech- 

 nique in the making up of stock solu- 

 tions of hematoxylin, like Delafield's, 

 in Albumen-Glycerin used for mounting 

 paraffin sections, etc. It serves as an 

 excellent clearing agent for the walls 

 of large Arteries so that the intramural 

 vessels can easily be distinguished by 

 the blood in them. With potassium 

 hydrate it is employed to clear speci- 

 mens in the demonstration of Ossifica- 

 tion centers. As a mounting medium 

 for frozen sections glycerin is invaluable. 

 In the form of Brandt's glycerin jelly 

 (which see) glycerin is specified in the 

 technique for Sebaceous Glands and 

 many other structures. To make Ilai- 

 ser's glycerin jelly (Mallory, p. 100) 

 soak 40 gms. gelatin in 210 cc. aq. dest. 

 for 2 hrs. Add 250 cc. glycerin, stir 

 and heat gently 10-15 min. Keep in 

 ice box and melt before use. The 5 

 gms. carbolic acid crystals specified in 

 Kaiser's formula has unfortunately, 

 according to Mallory, a deleterious 

 influence on alum hematoxylin prepara- 

 tions. See also Glychrogel and 

 Lactophenol. 



Glychrogel, as a mounting medium for teased 

 preparations, Marchi stained sections, 

 gelatin sections, etc. To make 100 cc. 

 dissolve 0.2 gm. chrome alum (potas- 

 sium chromium sulphate) in 30 cc. aq. 

 dest. with aid of heat. Add 3 gm. 

 Knox granulated gelatin in 50 cc. hot 

 aq. dest. Add 20 cc. glycerin with 

 constant stirring and warm. When 

 thoroughly mixed add crystal of camphor 

 (Wotton, R. M. and Zwemer, R. L., 

 Stain Techn., 1935, 10, 21-22). For 

 use in mounting nematodes (Wotton, 

 R. M., Stain Techn., 1937, 12, 145-146). 



Glycogen, the 3 chief microchemical meth- 

 ods have been critically studied by 

 C. M. Bensley (Stain Techn., 1939, 14, 

 47-52). This account follows her pre- 

 sentation. Since glycogen is labile, 

 immediate fixation of very small pieces 

 of tissue (2-3 mm.) and agitation of the 

 fixative are necessry. She recom- 

 mends 9 parts absolute ethyl alcohol -f 1 

 part commercial formalin (i.e. 37% 

 formaldehyde) neutralized with MgCOj. 

 If desired the alcohol in this fixative can 

 be saturated with picric acid. After 

 fixation for say 24 hrs. wash in aboslute 



alcohol, embed in the usual way in par- 

 affin (carefully avoiding overheating) 

 or in celloidin. 



1. Best's carmine. Griibler's car- 

 minum rubrum optimum or some 

 other good carmine 2 gm., potassium 

 carbonate 1 gm., potassium chloride 5 

 gm., aq. dest. 60 cc. Boil gently until 

 color darkens, cool and add 20 cc. con- 

 centrated ammonia. Allow to ripen 24 

 hrs. This is stock solution. Mount 

 paraffin sections, bring down to aq. 

 dest. Stain nuclei with hematoxylin 

 as in the H. and E. technique. Transfer 

 to fresh stain (stock solution 10 cc, 15 

 cc. cone, ammonia and 30 cc. pure 

 methyl alcohol) for 20 min. Rinse in 

 3 changes methyl alcohol, dehydrate in 

 acetone, clear in toluol and mount 

 in balsam. Glycogen brilliant red. 



2. Iodine (Gage). Mount paraffin 

 sections as before, being again careful 

 to avoid unnecessary heat, and bring 

 down to water. Lugol's aq. iodine 

 10-15 min. Blot with filter paper and 

 dry in air. Mount in yellow vaseline 

 as advised by S. H. Gage (J. Comp. 

 Neur., 1917, 27, 451-465) with minimum 

 of heat. Glycogen reddish brown. 



3. Bauer -Feidgen. To make Feulgen 

 reagent dissolve 1 gm. basic fuchsin in 

 100 cc. aq. dest. by heat. Filter while 

 warm and add when cool 20 cc. normal 

 HCI. Add 1 gm. NaHSOs. Allow to 

 rest 24 hrs., when it should be of pale 

 straw yellow color. Treat deparaffinized 

 sections with 4% chromic acid for 1 hr. 

 or with 1% chromic acid over night. 

 After washing in running water 5 min., 

 place in Feulgen reagent 10-15 min. 

 Rinse IJ min. in each of 3 changes of 

 molecular sol. NaHSOs 1 part and tap 

 water 19 parts. Wash in running 

 water 10 min. Counterstain nuclei with 

 hematoxylin if desired. Dehydrate, 

 clear and mount in balsam. Glycogen 

 deep reddish violet, nuclei lavender. 

 See Polysaccharides. 



Control. Prepare at same time some 

 sections of liver rich in glycogen. Be- 

 cause glycogen is quickly removed by 

 salivary digestion, when sample sections 

 are brought down to aq. dest., spit on 

 them and allow to rest 15-30 min. chang- 

 ing saliva several times. Wash thor- 

 oughly in water at body temperature 

 to remove mucus and stain by either of 

 the 3 above mentioned techniques. If 

 the material is then absent in such 

 sections and present in other similarly 

 stained and not digested, it is evidently 

 glycogen. Fixation by the freezing and 

 drying method is even better than with 

 the alcohol, picric, formalin mixture 

 because it is quicker and there is less 



