GIEMSA'S STAIN 



108 



GLYCOGEN 



cautions. The difficulty is that the 

 colors fade quite rapidly particularly 

 when the balsam is noticeably acid and 

 when the sections are left in direct 

 sunlight. Their period of usefulness 

 can be extended by mounting in cedar 

 oil, used for oil immersion objectives, 

 instead of in balsam. Try Clarite. 

 If a variety of fixatives is employed 

 it may be necessary to suit the stain to 

 the fixative by use of buffers, in which 

 case see Lillie, R. D., Stain Techn., 

 1941, 16, 1-6. 



To demonstrate the "nucleoids" of 

 bacteria in smears the technique of 

 C. F. Robinow published as Addendum 

 to Dubos, R. J., The Bacterial Cell. 

 Harvard Univ. Press, 1945, 460 pp. is 

 suggested. Fix smears in osmium 

 tetroxide vapor, treat 7-10 min. with 

 N/1 HCl at 60°C. and color with 

 Giemsa's solution. By this method nu- 

 cleoids are stained whereas similar 

 bacteria not treated with the acid are 

 uniformly colored by Giemsa. Robi- 

 now prefers this staining of nucleoids 

 by Giemsa after hydrolysis to the Feul- 

 gen technique. 



Gilson's Fluid. Nitric acid (sp. gr. 1.456), 

 15 cc; acetic acid, 4 cc. ; mercuric 

 chloride, 20 gm.; 60% ale, 100 cc; aq. 

 dest., 880 cc. Used mostly for inverte- 

 brates. 



Gilson's Mixture is equal parts chloroform 

 and cedar oil. 



Gingiva. Capillaroscopy of (McClung, p. 

 401). Eosinophile leucocytes in (Or- 

 ban, B., J. Dent. Res., 1940, 19, 537-543.) 



Glacial Acetic Acid, see Acetic Acid. 



Gland Cells contrasted. Endocrine, exo- 

 crine, apocrine, merocrine, holocrine, 

 serous, zymogenic and mucous (Cow- 

 dry's Histology, p. 257). 



Glia Staining with Anilin Dyes (Proescher, 

 Fr., Stain Techn., 1934, 9, 33-38). 

 Fix in 10% formalin or in 90% alcohol 

 followed by formalin. Wash frozen 

 sections, 10-15 microns thick, in aq. 

 dest. Stain in sat. aq. victoria blue B 

 (not filtered but poured off from the 

 undissolved dye), 14-24 hrs. Wash 

 quickly in aq. dest., mount with glyc- 

 erin-albumen, blot and dry in air. 

 Treat with ultraviolet light 30 min. 

 Pass to N/20 iodine few sec. Remove 

 iodine, blot, dry, destain in xylol- 

 anilin, clear first in clove oil, then 

 xylol, mount in balsam. Glia blue, 

 nerve cells lightly stained, connective 

 tissue metachromatic violet or colorless. 

 Instead of ultraviolet light stained 

 sections can be treated with 0.5% 

 potassium bichromatic for 30 min. In 

 place of victoria blue, methyl violet 2B, 

 ethyl violet or crystal violet can be 

 employed. 



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 inti'amural 

 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 Kai- 

 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 methods have been 

 critically studied by C. M. Bensley 

 (Stain Techn., 1939, 14, 47-52). This 

 account follows her presentation. Since 

 glycogen is labile, immediate fixation 

 of very small pieces of tissue (2-3 mm.) 

 and agitation of the fixative are neces- 

 sary. She recommends 9 parts absolute 

 ethyl alcohol + 1 part commercial 

 formalin (i.e. 37% formaldehyde) neu- 

 tralized with MgCOa. If desired the 

 alcohol in this fixative can be saturated 

 with picric acid. After fixation for say 

 24 hrs. wash in absolute alcohol, embed 

 in the usual way in paraffin (carefully 

 avoiding overheating) or in celloidin. 

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



