GASTRIC ICONTENTS 



106 



GIANT CELLS 



Gastric Contents. Examine microscopically 

 material obtained by stomach tube after 

 test meal as described by Stitt (p. 753). 

 Look for mucus, epithelial cells, leu- 

 cocytes. Gram positive bacilli in 

 smears. 



Gastrointestinal Tract. Immediate fixation 

 is desirable because postmortem changes 

 occur especially quickly. Do not wash 

 first with water but with physiological 

 saline or with the fixative itself. It may 

 be desirable to place the excised pieces, 

 with peritoneal surface down, on wooden 

 tongue depressor or stiff paper. Some 

 flattening is required. The mucous 

 surface must not be allowed to dry. 

 See Small and Large Intestine. 



Gautheria Oil used to be employed as a 

 clearing agent. It has been displaced 

 by the artificial oil, methyl salicylate. 



Geiger Counters are instruments for the 

 counting of electrons which provide 

 quantitative data of great importance 

 in this electron age. A concise descrip- 

 tion of the history of counter develop- 

 ment and of the Geiger-Muller type is 

 supplied by Rovner, L. in Glasser's 

 Medical Physics, 487-495. 



Gelatin-Carmine injections, see Carmine 

 Gelatin injections. 



Gelatin Glue, method of mounting sections, 

 see Masson's. 



Gelatin Imbedding and Sectioning. This is 

 used when sections are required of loose, 

 friable tissues which easily fall apart. 

 Since the imbedding is directly from 

 water, no alcoholic or other dehydration 

 is required. Probably the best method 

 is tliat of Zwemer (R. L., Anat. Rec, 

 1933, 57, 41-44), devised primarily for 

 the study of adrenal lipoids. Wash 

 material fixed in formalin or other fluid 

 in water, 4 hrs. 5% gelatin in incubator 

 at 35-37 °C . 24 hrs . 10% gelatin at same 

 temperature, 12-16 hrs. Imbed by 

 placing in 10% gelatin in Petri dish in 

 refrigerator. Cut out blocks of tissue 

 and fix in 10% formalin several hours 

 to make gelatin insoluble in water. 

 In this formalin solution tissues can be 

 preserved indefinitely. Before section- 

 ing rinse block in water and trim. 

 Freeze with CO2 until block is uniformly 

 white. Allow to thaw until knife cuts 

 easily. Sections as thin as 5 microns 

 can be obtained. Float onto slide in 

 aq. dest. Drain off excess water and 

 run a drop or two of 1% gelatin under 

 setion. Again drain off excess. After 

 heating in drying oven at 33-37°C. place 

 slide in 10% formalin for 10 min. to fix 

 gelatin. In this formalin solution the 

 mounted sections can be stored. Stain 

 sections in usu.al way with Sudan, Nile 

 Blue Sulphate, Osmic Acid, Laidlaw's 



Silver Method, and mount in Gly- 

 chrogel . 



Wright's method as described by 

 Mallory (p. 34) is much quicker and is 

 recommended for fragmented tissues 

 such as those from curettings. Make a 

 10% solution of gelatin in warm aq. 

 dest. and while still fluid add 0.5% 

 carbolic acid. Do not overheat. The 

 tissue, unfixed or fixed, preferably in 

 10% formalin, is "dried" and placed in 

 a small "pool" of gelatin liquified by 

 heat on a or slide in a glass vessel. This 

 is allowed to solidify in the ice box for 

 2 hrs. or more. If necessary, store 

 gelatin blocks in 10% formalin. Cut 

 out block containing the tissue, freeze 

 and section. Float sections from water 

 onto slide well coated with albumen- 

 glycerin and spread. Remove excess of 

 fluid and cover with piece of thin 

 cigarette paper. Blot with fine filter 

 paper till cigarette paper is partly dry. 

 Cover cigarette paper with equal parts 

 anilin oil and oil of cloves for few 

 seconds. Drain and peel off cigarette 

 paper. Remove oil by washing in 95% 

 alcohol and pass to water when sections 

 are ready for staining. Mallory suggests 

 methods for Amyloid, Fat and staining 

 with Hematoxylin and Phloxine for 

 general purposes. 



Gelatin Media, see Bacteria, Media. 



Gentian Blue 6B, see Spirit Blue. 



Gentian Violet. The problem afforded by 

 this dye, like many others, has been 

 attacked by the Stain Commission. 

 The stain thus referred to has no con- 

 stancy. Originally it was a mixture 

 in about equal parts of dextrin and 

 methyl violet, the latter itself a mixture 

 in widely varying proportions of tetra-, 

 penta- and hexa-methyl pararosanilins. 

 Later were placed on the market methyl 

 violets with and without dextrin and 

 crystal violet (the hexa methyl com- 

 pound) all imder the label of Gentian 

 violet. As Conn (p. 124) advises the 

 term Gentian violet should be elim- 

 inated and crystal violet used 

 wherever in the past the former has 

 been specified. See Neutral Gentian, 

 Methyl Violet, Crystal Violet. 



Geranine G (CI, 127). An acid tliiazole 

 dye employed in fluorescence studies 

 on account of color imparted by it 

 under ultraviolet illumination (Conn, 

 p. 70). 



Germanium, see Atomic Weights. 



Giant Cells. There is no special technique 

 for their demonstration. Since the 

 features usually employed in classifica- 

 tion are size and nuclear detail and 

 arrangement. Hematoxylin and Eosin, 

 or Iron Hematoxylin the latter followed 



