R.\DIOSODIUM 



215 



REGAUD'S METHOD 



is very high. Another isotope, Na" 

 has a half life of 3yrs., and may eventu- 

 ally prove quite useful. To date little 

 use has been made of this longer lived 

 isotope in biology. All references below 

 are to the Na^^ isotope. 



This lias been extensively employed 

 by Flexner, Gellhorn, and Pohl to deter- 

 mine rates of placental transfer in 

 mammals. See: Flexner, L. B. and 

 Pohl, H. A., J. Cell, and Comp. Physiol., 



1941, 18, 49-60; Am. J. Physiol., 1941, 

 134, 344-349; Gellhorn, A., Flexner, L. 

 B. and Pohl, H. A., J. Cell, and Comp. 

 Physiol., 1941,18, 385-392; and Flexner, 

 L. B. and Gellhorn, A., Am. J. Obst. 

 and Gynec, 1942, 43, 965-974. 



Radiostrontium (Sr^s) half life 55 days. 

 Distribution of this isotope in the body 

 is much like radiocalcium. The more 

 intense radiation from this element 

 than from radiocalcium makes it a possi- 

 ble choice for localized radiation therapy 

 of bones and osteogenic tissues. Auto- 

 radiographic and other evidence for 

 accumulation in a human osteogenic 

 sarcoma is presented by Treadwell, A. 

 deG., Low-Beer, B. V. A., Friedell, H. L. 

 and Lawrence, J. H., Am. J. Med. Sci., 



1942, 204, 521-530. 



Radiosulphur (S^^) half life 88 days. The 

 metabolism of radiosulphur in inorganic 

 salts and in synthetically prepared 

 thiamine chloride (vitamin Bi) in nor- 

 mal and vitamin deficient human sub- 

 jects lias been studied by Borsook and 

 his coworkers (Borsook, H., Hatcher, 

 J. B. and Yost, D. M., J. Appl. Phys., 

 1941, 12, 325A and earlier papers). 



Ranson Pyridine method for unmyelinated 

 nerve fibers (Ranson, S. W., Rev. 

 Neurol. & Psychiat., 1914, 12, 467-474). 

 Fix in absolute alcohol + 1% ammonia, 

 48 hrs. Rinse in aq. dest. and treat 

 with pyridine, 24 hrs. Wash repeatedly 

 in aq. dest., 24 hrs. 2% aq. silver nitrate 

 at 35°C. in dark, 3 days. Rinse in aq. 

 dest. Reduce in: pyrogallol, 4 gm.; 

 5% formalin in aq. dest., 100 cc. Wash 

 and imbed in paraffin. This much used 

 technique gives a fine blackening of 

 unmyelinated fibers. See also Ranson, 

 S. W. and Billingsley, P. R., J. Comp. 

 Neurol., 1918, 29, 313-358; Johnson, S. 

 E.,ibid, 1928, 38, 299-314). The latter 

 believes the essential features of the 

 technique to be vascular perfusion with 

 physiological saline solution followed 

 by 1% ammonia in absolute alcohol. 



Ranvier's Gold Chloride method for nerve 

 endings in muscle, see Craven's and 

 Carey's methods. See also Ammonia 

 Carmine and Picrocarmine of Ranvier. 



Reconstruction. Stereoscopic x-ray method 

 (Morton, W. R. M., J. Anat., 1940-41, 

 75, 265-2G6) ; wax plate method as ap- 

 plied to the stapes (Anson, B. J., Kara- 



bin, J. E. and Martin, J., Arch. Oto- 

 laryng., 1939, 29, 939-973). 



Red B, see Oil Red O. 



Red Blood Cell, see Erythrocyte. 



Red Corallin, (CI, 726) . Look up in Colour 

 Index. 



Red Violet, see Hofmann's Violet. 



Redox dyes are those employed in reduc- 

 tion-oxidation potential determina- 

 tions, see Oxidation-Reduction Po- 

 tential. 



Reed-Sternberg Cells. Recognition of 

 these cells is helpful in reaching a diag- 

 nosis of Hodgkin's disease. Special 

 technique other than Hematoxylin and 

 Eosin is ordinarily not necessary. 

 Comparison by Jackson, H., Jr. and 

 Parker, F., Jr., New England J. Med., 

 1944, 231, 35-44 of Reed-Sternberg Cells 

 with certain other multinucleated cells 

 will be helpful. The use of tissue cul- 

 ture technique in their investigation 

 opens many promising leads (Grand, 

 C. G., Proc. Soc. Exp. Biol. & Med., 

 1944, 56, 229-230). Thus, it should be 

 possible to determine their life history 

 and check on the suggestion that the 

 hyperchromatic Sternberg Cells are a 

 later development of Reed cells (Ber- 

 sack, S. R., Am. J. Clin. Path., 1943, 

 13, 253-259). The cytoplasmic inclu- 

 sions, reported by Grand, are sugges- 

 tive of virus action. The claim of Sym- 

 mers, D., J. A. M. A., 1945, 128, 1248- 

 1249, that these cells should be called 

 Greenfield Cells in honor of Greenfield's 

 first description in 1878 will probably 

 not be followed. 



Refractive Index. Microscopical deter- 

 mination bystandard liquids. See paper 

 by Kunz, A. H. and Spulnik, J., Re- 

 viewed in J. Roy. Micr. Soc, 1937, 57, 

 55. 



Regaud's Fluid. 3% aq. potassium bi- 

 chromate, 20 cc; formalin, 5 cc. When 

 this is used for mitochondria fix tissue 

 for 4 days changing every day and then 

 mordant in 3% aq. potassium bichro- 

 mate for 7 days changing every second 

 day. It is a fluid that can be profitably 

 employed for many other purposes. 

 Of these see Giemsa's Stain, Lead, 

 Masson's Trichrome, Romieu Reac- 

 tion and Starch Grains. 



Regaud's Method of iron hematoxylin for 

 mitochondria. Fix tissues in Regaud's 

 fluid, mordant, imbed and section as 

 described under Anilin Fuchsin Methyl 

 Green Method. Run mounted sec- 

 tions down to water and mordant for 

 24 hrs. in 5% aq. iron alum. Rinse 

 quickly in aq. dest. (not tap water) 

 and transfer to hematoxylin (made by 

 dissolving 1 gm. hematoxylin crystals 

 in 10 cc abs. ale adding 10 cc. glycerin, 

 80 cc. aq. dest. and allowing to ripen 

 3 weeks). If traces of iron alum are 



