METHYL BLUE 



150 



METRIAL GLAND 



47 pp. See Mann's Methyl-Blue Eosin 

 and staining of Elementary Bodies. 

 Methyl Blue-Eosin, see Mann's. 



Methyl Eosin (CI, 769). The methyl ester 

 of eosin Y, see Eosins, choice of. 



Methyl Green (CI, 684)— double green, 

 light green — This basic triphenyl meth- 

 ane dye is crystal violet (hexa-methyl 

 pararosanilin) into which a seventh 

 methyl group has been incorporated. 

 Conn (p. 130) points out that this is 

 loosely bound so that some methyl or 

 crystal violet is always present with the 

 methyl green to which circumstance the 

 metachromatic properties of the dye are 

 partly due. Methyl green is not as 

 stable as most dyes and cannot therefore 

 be kept too long in the powdered state. 

 It is very similar to Ethyl Green. 



Methyl Green-Pyronin (Pappenheim). Sec- 

 tions of formalin-Zenker fixed tissues 

 are stained about 6 min. in : methyl 

 green 0.5 gm.; pyronin Y, 0.5 gm.; ale. 

 2.5 CO.; glycerin 20 cc; aq. dest. 0.5% 

 carbolized 100 cc. Rinse in aq. dest.; 

 dehydrate in acetone; clear in cedar 

 oil followed by xylol and mount. Opti- 

 mum time of staining must be deter- 

 mined experimentally. A brilliant 

 stain particularly for lymphocytes and 

 plasma cells. Very useful for spleen 

 and lymph nodes. (Slider and Downey 

 in McClung's Microscopical Technique, 

 p. 342). 



Methyl Orange (CI, 142)— gold orange MP, 

 helianthin, orange III, tropaeolin D — 

 A slightly acid mono-azo dye widely 

 employed as an Indicator. 



Methyl Red (CI, 211). A slightly acid 

 mono-azo dye widely used as an Indica- 

 tor. See also Carter, J. S., J. Exp. 

 Zool., 1933, 65, 159-179 for vital staining 

 of rabdites of Stenostomum with 

 methyl red. 



Methyl Salicylate (oil of Wintergreen) is 

 employed in Spalteholz Method of 

 clearing. 



Methyl Violet (CI, 680)— dahlia B, gentian 

 violet, Paris violet, pyoktaninum coeru- 

 leum — Exists in various shades 2R, R, 

 B, 2B, 3B, etc., depending upon propor- 

 tions of the mixture of tetra-, penta- 

 and hexa-methyl rosanilins. R indi- 

 cates reddish and B bluish. 2B is the 

 one which Conn (p. 123) regards as most 

 satisfactory whenever methyl violet, 

 or one of the redder types of gentian 

 violet, is requested. (It is Commission 

 Certified.) The pure hexamethyl com- 

 pound is called crystal violet — a dye 

 much in demand. See Hydrogen Ion 

 Indicators. 



Methylene Azure (CI, 923). Abasic thiazin 

 dye long recognized as a component of 

 Polychrome Methylene Blue. Conn 

 (p. 76) says that the term, methylene 



azure, should be discarded because it 

 is composed of three components Azure 

 A, B, and C which see. 



Methylene Blue (CI, 922)— Swiss blue- 

 Conn (p. 80) says that this basic thiazin 

 dye is theoretically tetra-methyl thio- 

 nin but the homologues of lower 

 methylation are practicallj^ always 

 present ; he lists the following grades : 

 methylene blue BX, B, BG, BB, and 

 methylene blue chloride. The last 

 named is Commission Certified and least 

 toxic. Methylene blue Med. U.S.P. 

 is required to be zinc free and is also 

 satisfactorJ^ New methylene blue N 

 (methylene blue NN) is a basic dye of 

 the same type but of a slightly greener 

 shade. Conn (McClung, p. 595) states 

 that it was apparentlj' in certain lots 

 of prewar methylene blue. Methylene 

 blue O is the same as toluidin blue O 

 which resembles azure A, a component 

 of methylene azure produced by poly- 

 chromizing methylene blue. Another 

 of the series is methylene blue GG but 

 it has no particular advantage. Prob- 

 ably no dye, other than hematoxj'lin and 

 eosin, is more widely used. The oxida- 

 tion products of methylene blue are 

 described by Holmes, W. C, Stain 

 Techn., 1926, 1, 17-26 and the influence 

 of pH on staining of plasma cells and 

 lymphocytes bv Kindred, J. E., Stain 

 techn., 1935, 10, 7-20. Its cytological 

 action has been fully studied by Lud- 

 ford, R. J., Arch. f. exp. Zellf., 1935. 

 17, 339-359. It is an excellent counter- 

 stain for Acid Fast Bacilli. See Poly- 

 chrome Methylene Blue, Loeffler's 

 Alkaline Methylene Blue, Nerve End- 

 ings, Phloxine Methylene Blue, Mac- 

 Neal's Tetrachrome, Pancreas, Pro- 

 tozoa, etc. 



Methylene Blue NN, see New Methylene 

 Blue N. 



Methylene Blue T 50 or T Extra, see Toluidin 

 Blue O. 



Methylene Blue Eosinate, see May-Griin- 

 wald fixative and stain. 



Methylene Green (CI, 924). This basic 

 thiazin dye is mono-nitro methylene 

 blue. Conn (p. 86) says that it is oc- 

 casionally employed as a substitute for 

 methyl green and gives good results as 

 counterstain for eosin. 



Methylene Violet. Commission Certified. 

 This feebly basic thiazin dye is, as 

 Conn (p. 86) explains, formed whenever 

 methylene blue is heated with a fixed 

 alkali or alkali carbonate. It may be 

 purified bj' recrystallization but little 

 is to be gained. The dye is not much 

 used. 



Melrial Gland. This is a transitory struc- 

 ture of unknown function in the mouse 

 appearing at approximately the 8th day 



