184 CHAPTER XV. 



pass through bergamofc oil, or xylol or benzol {not clove-oil) 

 into balsam. Brings out bacteria (red) in organic liquids. 

 The mixture may be had from Grubler & Hollborn. 



293. Orange G. — This is the benzenazo-beta-naphthol- 

 disulphonate of soda (to be obtained from G-riibler & Hollborn, 

 and not to be confounded with about a dozen other colours 

 that are on the market under the name of " Orange," with 

 or without a suffix). As indicated by its chemical description, 

 this is an "acid" colour. 



It is easily soluble in water, less so in alcohol. Use as 

 directed for Siiui-efuchsin. Almost, if not quite, as precise a 

 stain as Saurefuchsin. It does not overstain, but may wash 

 out other dyes. 



294. Saurefuchsin and Orange G. — I have had good results 

 by mixing the aqueous solutions of these two dj^es, but unfor- 

 tunately have not noted the proportions. Squire {Methods 

 and Formulw, p. 42) takes 1 grm. Saurefuchsin, 6 grms. 

 Orange Gr. in 60 c.c. of alcohol, and 240 c.c. of water. See 

 also under " connective tissues." 



295. Ehrlich-Biondi Mixture (or Ehei.ich-Biondi-Hei- 

 DENHAiN Mixture) {Pfliiger's Arch., xliii, 1888, p. 40). 



To 100 c.c. saturated aqueous solution of orange add with 

 continual agitation 20 c.c. saturated aqueous solution of 

 Saurefuchsin (Acid Fuchsin) and 50 c.c. of a like solution of 

 methyl green. 



(According to Krause [Arch. mil-. ^■no<.,xlii, 1893, p. 59], 100 parts of 

 water will dissolve about 20 of Saui-efucLsin [Rubin S], 8 of orange G. 

 and 8 of methyl green.) The solutions must be ahsolidely saturated, 

 which only happens after several days. 



Dilute the mixture with 60 to 100 volumes of water. The 

 dilute solution ought to redden if acetic acid be added to it ; 

 and if a drop be placed on blotting-paper it should form a 

 spot bluish green in the centre, orange at the periphery. If 

 the orange zone is surrounded by a broader red zone, the 

 mixture contains too much fuchsin. 



According to M. Heidenhain (" Ueber Kern u. Proto- 

 plasma," in FcMschr. f. KoUil-pv, 1892, p. 11.5) the orange to 

 be used should be " Orange Gr"; the Acid Fuchsin or Siiure- 



