GELATIN MEDIA 



139 



GIEMSA'S STAIN 



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. 



Gelatin-Ringer electrode vessel, modifica- 

 tion by Kriest, A. C, Acta Physiol, et 

 Pharmacol. Neerland., 1950, 1, 32-34. 



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 under 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 thiazole 

 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 

 by various counter stains as for Acid 

 Fast Bacilli are recommended. The 

 following is a much abbreviated classi- 

 fication of Giant Cells from Cowdry's 

 Histology 1938 Edition : 



1. Megakaryocytes of bone marrow, 

 granules in cytoplasm, best demon- 

 strated by Giemfsa's Stain. 



2. Foreign body gianl cells formed 

 probably by a fusion of cells of mesen- 

 chymatous origin, perhaps of non- 

 granular leucocytes, in response to 



foreign materials of many kinds — 

 tubercular giant cells, foam cells in 

 leprosy, lympsocystic giant cells of fish 

 (Weissenberg), and possibly Reed- 

 Sternberg cells in Hodgkin's disease. 



3. Osteoclasts (polj^karyocytes) of 

 bone marrow and Langhans' giant cells 

 of placenta are normal inhabitants of 

 these organs. Myeloplague and Myelo- 

 plax are other terms for osteoclast. 

 Chorioplague is a plate like giant cell 

 of the chorion. See original account 

 for lack of specific properties of so- 

 called Langhans' cells which designa- 

 tion should be abandoned. 



4. Epithelial giant cells are clearly of 

 epithelial origin. Found in epidermis 

 in chicken-pox and other diseases, oc- 

 casionally in the liver and in kidney in 

 many conditions. Often show nuclear 

 irregularity and evidence of nuclear 

 budding. 



5. Hypertrophied cells can be either 

 normal to meet physiological demands, 

 as enormously enlarged smooth muscle 

 cells of pregnant uterus, or due to vari- 

 ous pathological conditions. Mauth- 

 ner's Giant Cell in the fish brain is al- 

 ways of tremendous size in adults. 



Giemsa's corrosive sublimate fixative. Sat. 

 aq. corrosive sublimate 2 parts, absolute 

 alcohol 1 part. 



Giemsa's Stain. 1. For hlood or bacteria 

 in smears. Fix air dried smears in 

 methyl alcohol in a covered dish 3-4 

 minutes. Remove and blot dry. Di- 

 lute stock solution of Giemsa in propor- 

 tion of 1 drop to 1 cc. aq. dest. and stain 

 for 15 minutes. Then wash in aq. dest., 

 blot and dry. If a precipitate is formed 

 in the smear by the stain, invert the 

 slide, support both ends, and the stain 

 will adhere like a hanging drop, kept 

 away from the ends by lines ruled in 

 wax or paraffin. The pH of the aq. dest. 

 used to dilute the stain may be altered 

 by adding very dilute acid or alkali. 

 Optimum pH of 6.4 is given by the 

 McJunkin-Haden buffer. This may be 

 used as diluting medium in place of aq. 

 dest. Usually the azurophile are 

 stained more distinctly and the neutro- 

 phile granules less sharply than by 

 Wright's stain. Bacteria and intra- 

 cellular protozoa are better colored than 

 by Wright's stain. The May-Giemsa, 

 and Jenner-Giemsa and the panchrome 

 stains of Pappenheim are important 

 modifications. They are listed sepa- 

 rately. Present situation concerning 

 Giemsa's stain is that American 

 products give equally good results with 

 thin films but the German product 

 appears to be better for thick ones 

 (Conn, H. J., Stain Techn., 1940, 15, 

 41-43). 



