NtTRO REACTION 



172 



NORMAL SOLUTIONS 



nitrified (Lison, p. 162). See Lison, 

 L., J. PhysioL et Path. Gen., 1933, 31, 

 82-99). 

 Nitroprusside Reaction for Glutathione. 



1. Mattei and Dulzetto (Atti. e. rend, 

 della Accad. dei Lincei, 1928, 8, 317). 

 Fix in 20% trichloracetic acid. Treat 

 frozen sections 3-4 min. with a fresh 

 solution of sodium nitroprussiate. After 

 quickly drying expose to NH3 vapor. 

 Freeze solidly with ice or solid CO2. 

 E.xamine frozen on slide at 5°C. The 

 violet color of sulphydryl rapidly disap- 

 pears. 



2. Joyet-Lavergne (Ph., Bull. d'Hist., 

 1928, 5, 331-349) Method 1: apply to 

 tissue 1 drop 5% aq. sodium nitroprus- 

 siate, then 1 drop ammonia and examine 

 immediately. Method 2 : before apply- 

 ing reagent as above he uses a stimulant 

 10% aq. potassium cyanide, 5 min.; or 

 2% aq. sodium sulphite, 10 min., or sat. 

 ammonium sulphate, 15 min., or tri- 

 chloracetic acid, 2-5 min. Method 3 for 

 fixed tissues : fix several hours in abs. 

 ale. or in formol 15 cc. + physiological 

 saline sol. 75 ce. Tease tissue or make 

 frozen sections. Stimulate with potas- 

 sium cyanide or ammonium sulphate. 

 Then apply reagent. 



3. Giroud and Bulliard (A. and H., 

 Protoplasma, 1933, 19, 381-384). Apply 

 to fresh teased tissues or frozen sections 

 10% aq. sodium nitroprussiate alka- 

 linized by about 2% ammonia. Fix the 

 color by treatment for several seconds 

 with 5% aq. zinc acetate. Dehydrate, 

 clear and mount in balsam in the usual 

 way. The violet color becomes red but 

 lasts some time especially if kept in ice 

 box. The same technique is possible 

 after alcohol fixation. 



Lison (p. 135) has considered the spec- 

 ificity of these reactions and recom- 

 mends analysis given in an article by 

 Rapkine contained in the last edition 

 of Langeron's Precis de Microscopic. 

 For fresh tissues (pieces, smears, frozen 

 sections) (a) Glutathione reduced. Add 

 to tissue on slide 1 drop 5% sodium 

 nitroprusside for plants, 2% for animals. 

 Add a reinforcer such as sat. aq. am- 

 monium sulphate or crystals, then drop 

 of ammonia. Red or violet color, (b) 

 Glutathione total. Treat tissue with 10% 

 cyanide of potassium, 5-10 min. Then 

 (a), (c) SH radicals fixed to proteins. 

 10% trichloracetic acid 15 min. Wash 

 in much water. Repeat several times. 

 For fixed tissues avoid employing 

 absolute alcohol or trichloracetic acid. 

 Use instead formol -saline (above). 

 Then follow as for fresh tissues. Fix 

 colors with zinc acetate as described. 



Bourne (G., Austral. J. Exp. Biol. & 

 Med. Sci., 1935, 13, 238-249) puts frozen 

 sections into hot 5% aq. acetic acid 



30-90 sec; drains off the acid; adds 5% 

 sodium nitroprusside (saturated with 

 ammonium sulphate) 2 min., then few 

 drops cone, ammonium hydroxide which 

 turns them purplish blue. For quanti- 

 tative unreliability of the test for -SH 

 and -S.S- see Hammett and Chapman, 

 (F. S. and S. S., J. Lab. & Clin. Med. 

 1938-39, 24, 293-298). 



Nitrosamino Reaction of Lison (p. 161) 

 consists in transforming the amino group 

 present in pyrrol and indol into nitrosa- 

 mine by action of nitric acid; then by 

 demonstrating the nitrosamine by the 

 reaction of Liebermann. 



Nitroso Dyes (quinone o.ximes). Produced 

 by nitrous acid acting on phenolic com- 

 pounds. Naphthol gieen B and Y. 



NNN Medium, see Leisiimania. 



Nocht's Stain for malaria plasmodia is de- 

 scribed by Craig, p. 287 as less satis- 

 factory and more time consuming than 

 Wright's. 



Nonfilament-Filament Ratio. This is de- 

 rived from the Filament-Nonfilament 

 Count, the number of nonfilamented 

 neutrophiles being multiplied by 100 

 and divided by the number of filamented 

 ones. See Stiles, M. H., J. Lab. & 

 Clin. Med., 1940-41, 26, 1453-1460. 



Nopalin G, see Eosin B or bluish. 



Normal Solutions. The equivalent of a 

 substance (eqviivalent weight, the gram 

 equivalent) is the weight in grams which 

 in its reaction corresponds to : a gram 

 atom of hydrogen, or of hydroxyl, or a 

 univalent ion, or to half a gram atom of 

 oxygen. A normal solution contains 

 one equivalent per liter, a 0.05 normal 

 contains 0.05 equivalent. 



Hydrochloric acid (HCl), the molecu- 

 lar weight is H = 1.008 -f CI = 35.457 

 (see Atomic Weights) = 36.465. Con- 

 sequently make up 36.465 gms. of HCI 

 to 1 liter with aq. dest. But it can not 

 be weighed out in this way. Since 

 cone, hydrochloric acid (sp. gr. 1.19) 

 is appro.ximately 12 N, to make a normal 

 solution (approximate) dilute 83.3 cc. 

 to 1 liter with aq. dest. The normality 

 can be accurately determined by stand- 

 ardizing with sodium carbonate, or by 

 titration with a solution of sodium 

 hydroxide of known normality. 



Sulphuric acid is H2SO4- Molecular 

 weight calculated in the same way is 

 130.136. But there are 2 replaceable 

 hydrogen atoms so that in makinga nor- 

 mal solution the molecular weight is 

 divided by 2 which means that 65.068 

 gms. of H2SO4 is to be made up to 1 liter 

 with aq. dest. A cone. sol. (sp. gr. 

 1.84) is approximately 36 N. To make 

 approximately 1 N dilute 27.8 cc. to 

 1 liter. 



Oxalic acid has the formula (C00H)2- 

 2HjO with molecular weight of 126. 



