NEW PINK 



229 



NINHYDRIN REACTION 



New Pink, see Phloxine. 



New Ponceau 4R, see Ponceau 2R. 



New Victoria Blue B or R, see Victoria 

 Blue R. 



New Victoria Green Extra O, I or II, see 

 Malachite Green. 



Niagara Blue 3B, see Trypan Blue. 



Niagara Blue 4B (CI, 520) — benzo sky blue, 

 direct sky blue, pontamine sky blue 

 5BX — A disazo dye, see Varrelman, 

 F. A., Stain Techn., 1938, 13, 115-119. 

 Niagara blue 2B (N.A.C.) is the Ameri- 

 can prototype of trypan blue for which 

 it can be substituted (Foot, McClung, 

 p. 115). 



Niagara Sky Blue 6 B (CI, 518), a direct di- 

 sazo dye of light fastness 3. Instruc- 

 tions for employing this useful stain in 

 the examination of plant and animal 

 tissues are given (Emig, p. 41). 



Nickel. The microchemical technique of 

 Cretin and Pouyanne (A., and L., 

 Bordeaux chirurgical, 1933, 4, 321-364) 

 employed in a study of the influence of 

 metals on bone deposition, as given by 

 Lison (p. 102), is: Fix in formol, 30 cc, 

 "s6rum physiologique", 100 cc, ana 

 ammonium hydrosulphate 5 drops. Im- 

 merse in a solution of ammonium 

 phosphate in order to produce the 

 insoluble double salt: NHiNiPO^ + 

 6H2O. Decalcify. In the sections stain 

 the nickel by an alcoholic solution of 

 pure hematoxylin which forms a lilac 

 colored nickel lake appearing blue when 

 very thick (Lison, p. 102). 



Nicotinic Acid. Preliminary detection of it 

 or its amide by fluoresence microscopy 

 (Hirt, A. and Wimmer, K., Klin. Woch- 

 nesdir., 1939, 18, 765-767). Lasting 

 yellow fluorescence. See Vitamin B 

 complex. 



Night Blue (CI, 731), a basic dye of light 

 fastness 4 gives beautiful blue-violet 

 coloration of plant tissues but fades 

 (Emig, p. 52). 



Nigrosin, water soluble (CI, 865) — gray 

 R, B, BB, indulin black, silver gray, 

 steel gray — Commission Certified. This 

 is a mixture. It has been used as a 

 counterstain for neutral red in colora- 

 tion of Nissl bodies by Bean, R. J., 

 Stain Techn., 1927, 2, 56-59, as a nega- 

 tive stain for bacteria, Treponema, etc. 

 See Picro-Nigrosin. 



Nile Blue A, see Nile Blue Sulphate. 



Nile Blue Sulphate (C 1. 913)— Nile Blue A 

 — This is an important oxazin dye for 

 which purity tests have been estab- 

 lished (Conn, p. 270). It was intro- 

 duced by Lorrain Smith as a fat stain. 

 Briefly the method is to stain fresh 

 tissues, or frozen sections of formalin 

 fixed tissues, for 10-20 min. in a cone, 

 aq. solution of Nile blue sulphate, to 

 differentiate in 1% aq. acetic acid, 



wash in water and mount in glycerin. 

 He thought that the neutral fais {glycer- 

 ides) were thereby colored red and the 

 fatty acids blue, but Kaufmann and 

 Lehmann (C. and E., Virchow's Arch, 

 f. Path. Anat. und Physiol., 1926, 261, 

 623-648) came to the conclusion that the 

 method was valueless. However Lisson 

 (p. 202) was unimpressed by their 

 evidence. In his opinion the rose (or 

 red) color does signify the presence of 

 a nonsaturated glyceride whereas the 

 blue color is of no significance because of 

 its lack of specificity. He reported 

 that some mixtures of free fatty acids 

 remain uncolored; for those containing 

 saturated fatty acids non -coloration is 

 the rule; while some others, not con- 

 taining fatty acids, are colored. See 

 Lipids, tabular analysis. 



Stone, L. S., Anat. Rec, 1931, 51, 

 267-273 has advanced a technique for 

 the preservation of supravital staining 

 with Nile blue sulphate the essential 

 feature of which is repeated treatment 

 with phosphomolybdic acid. Zenker's 

 fluid with acetic, 2 hrs. Running tap 

 water, 1 hr. 1% aq. phosphomolybdic 

 acid, 2 hrs. Dehydrate in 50, 70, 80, 95 

 and abs. ale. each containing 0.1% 

 phosphomolybdic acid, 30 min. each. 

 Clear in equal parts 0.1% phospho- 

 molybdic acid in abs. ale. and cedar 

 wood oil, 30 min. Then pure cedar wood 

 oil over night. Embed in paraffin 3 

 changes 15-20 min. each. Counterstain 

 sections in stain desired applied in abs. 

 ale. containing 0.1% phosphomolybdic 

 acid. Mount in damar. Balsam will do. 



Nile Pink, fat stain prepared from nile 

 blue sulphate by boiling with dilute 

 sulphuric acid (Rettie, T., J. Path. & 

 Bact., 1931, 34, 595-596). 



Ninhydrin Reaction. Berg's (W., Pfluger's 

 Arch., 1926, 214, 243-249) directions: 

 Fix tissues in 10% formalin, wash in 

 water. Boil section for 1 min. in 2 cc. 

 0.2% ninhydrin. Wash, mount in glyc- 

 erin or glycerin jelly. Amino acids, 

 polypeptides and proteins blue or violet. 

 Romieu (M., Bull. d'Hist. AppL, 1925, 

 2, 185-191) employs a strong solution 

 heated less. See Giroud (A., Proto- 

 plasma, 1929, 7, 72-98). 



Details are given by Serra, J. A., 

 Stain Techn., 1946, 21. 5-18. He ad- 

 vises that the tissue first be hardened 

 by fixation for an unspecified time in 2 

 parts 96% alcohol and 1 part commercial 

 formalin (40% formaldehyde) plus 

 "some drops" of glacial acetic acid in 

 10 cc. of the mixture. After this it is 

 well washed in running water and in aq. 

 dest. before the frozen sections are 

 made. He also gives a method for 

 paraffin sections. 



