GRAM-TWORT STAIN 



151 



HAIRS 



existing in nature. There are many 

 intermediates between the two, and 

 this fact should be kept in mind by the 

 technician. Attempts to create termi- 

 nology for intermediate groups have 

 not been well received and the classifi- 

 cation as it now stands is extremely 

 useful and comparitively simple. Fur- 

 ther information is supplied by 

 Bartholomew, J. W. and Umbreit, W. 

 W., J. Bact., 1944, 48, 567; Bartholo- 

 mew, J. W. and Mittwer, T., Stain 

 Tech., 1949, 25, 103-110; Dubos, R. J., 

 The Bacterial Cell. Cambridge: Har- 

 vard Univ. Press, 1946, pp. 72-85; 

 Knaysi, G., Elements of Bacterial 

 Cytology. Ithaca: Comstock Pub. Co., 

 1951, pp. 267-278; Mittwer, T., Bar- 

 tholomew, J. W., and Kallman, B. J., 

 Stain Tech., 1950, 25, 169-179. 



Gram-Twort Stain. For study of Gram- 

 positive and Gram-negative bacteria 

 in sections (Ollett, W. S., J. Path. & 

 Bact., 1947, 59, 357). Twort originally 

 used a neutral red-light green mixture. 

 Ollett, W. S., J. Path. & Bact., 1951, 

 63, 166 supplies further details. The 

 stain advised is approximately as fol- 

 lows depending on dye content of the 

 samples employed. For stock solution 

 0.2% ale. neutral red, (CI no. 825 9 ml. 

 + 0.2% ale. fast green FCF 10 ml. 

 For use dilute 1 vol. stock solution with 

 3 vols. aq. dest. Employ as counter- 

 stain in Gram's method as described 

 (Ollett, 1947) and mount sections in 

 L. P. M. which is Lustron (L 2020), 

 apparently the same as Distreme 80 

 crystal clear 100 gm. dissolved in Di- 

 butyl phthalate 50 ml. + monochlor- 

 benzene 300 ml. 



Gray, R, B, BB, see Nigrosin, water soluble. 



Green PL, see Naphthol Green B, 



Greene, see Anterior Chamber Transplanta- 

 tion. 



Gregarines. Technique given by McCIung, 

 Microscopical Technique, 1950 p. 455. 

 Fix in picric acid mixtures. Stain 

 smaller ones in Heidenhain's Iron 

 Hematoxylin and larger ones with 

 Hemalum. For Golgi bodies see Joyet- 

 Lavergne, P., C. R. Soc. de Biol., 1926, 

 94, 830. 



Grenacher, see Alum Carmine, Borax 

 Carmine. 



Grieves' method for undecalcified dental 

 tissues and bone as outlined by Shipley 

 (McClung, p. 345) is: Fix small pieces 

 in 10% formalin 24-36 hrs. or any other 

 desired fixative. Wash in running water 

 24 hrs. Then pass through 2 changes 

 of aq. dest. 1 hr. each. Dehydrate 

 through ascending alcohols beginning 

 with 50% ale. Equal parts abs. ale. 

 and chloroform, 2 hrs. Chloroform, 2 

 hrs. 5% sol. of rosin in chloroform, 2 



hra. 10% sol. rosin, 2 hrs. Sat. sol. 

 rosin until it becomes transparent. 

 Imbed in melted rosin using one after 

 another the rosins in 3 small glass dishes 

 on a heated copper bar, 1 min. each. 

 The chloroform carried over evaporates. 

 The rosin containing the tissue is al- 

 lowed to cool. The block is ground 

 very thin by hand on a carboriundum 

 stone and polished on a fine hone all 

 grinding being done under luke warm 

 water. The smooth surface is then 

 mounted on a slide with a little melted 

 rosin after which the surface is ground 

 and polished in the same waj' and the 

 section is ready for mounting or for 

 staining. 



Gross Specimens, see Color Preservation. 



Ground Substance (intercellular), see Tis- 

 sue Fluid. 



Growth. Many techniques are now avail- 

 able for the measurement of growth of 

 tissues. Increase in number of cells 

 can be revealed by mitotic counts 

 (Mitosis). The amount of bone or of 

 dentine laid down while Alizarin S 

 or Madder is in the circulation can be 

 estimated. The amount of radioactive 

 isotropes accumulated is a third method 

 (see Radioactive Phosphorus) if the 

 amount increases per unit of time while 

 elimination of the nonradioactive ele- 

 ment in question remains the same. 

 Valuable histochemical methods are 

 given by Lowry, O. H. and Hastings, 

 A. B., in Cowdry's Problems of Ageing, 

 Baltimore : Williams and Wilkins, 1942, 

 936 pp. 



Gout, see Urates. 



Guanin appears as white granules in retinal 

 tapetum of certain animals including 

 nocturnal ones. Decreases in amount 

 in regions containing more fuscin. 

 For details see Arey, L. B. in Cowdry's 

 Special Cytology, 1932, 3, 1218. 



Guanine, see microxide test under Purines. 



Guarnieri Bodies, cytoplasmic inclusions in 

 smallpox and vaccinia. See Inclusion 

 Bodies and Cowdry, E. V., J. Exper. 

 Med., 1922, 36, 667-684 for supravital 

 staining with brilliant cresyl blue. For 

 sections Giemsa's stain is excellent. 



Gum Damar, see Damar. 



Gypsum test, see Calcium 7. 



Habermann, see Anethole Clearing Agent. 



Hafnium, see Atomic Weights. 



Hairs — Written by Mildred Trotter and 

 Oliver H. Duggins, Dept. of Anatomy, 

 Washington University, St. Louis, May 

 8, 1951 — The hair shaft (above the sur- 

 face of the skin), the hair root (below 

 it) and the hair follicle (encasing the 

 root) call for somewhat different 

 techniques. 



The shaft may be examined in a dry 

 mount after first washing thoroughly 



