162 COMBINATION STAINS. 



Stain sections for six to twenty-four hours. Wash out with 

 alcohol, clear with xylol, and mount in xylol balsam. 



According to M. HEIDENHAIN'S most recently published in- 

 structions (" Ueber Kern u. Protoplasma," in Festschr. Herrn 

 Geh. A. v. Kolliker gewidm., &c., 1892, p. 115 ; see Zeit.f. wiss. 

 Mik., ix, 2, 1892, p. 202) the Orange to be used should be 

 " Orange G ; " the Acid Fuchsin or Saurefuchsin should be 

 " Rubin S " (" Rubin " is a synonym of Fuchsin) ; and the 

 Methyl Green should be "Methylgriin 00." And it is 

 absolutely necessary that these ingredients be those prepared 

 under those names by the Actienfabrik filr Anilin fabrication 

 in Berlin. 



The strong solutions directed to be taken readily precipi- 

 tate on being mixed. To avoid this it is recommended by 

 SQUIRE (Methods and Formulae, &c., p. 37) to dilute them 

 before mixing. 



If (HEIDENHAIN, Arch. f. mik. Anat., xxxv, 1890, p. 173; 

 Zeit. f. wiss. MiJc., vii, 3, 1890, p. 357) the alcohol used for 

 washing out be slightly- alkaline, the stain of the fuchsin will 

 become relatively pale in the result, and the stain of the 

 methyl green relatively strong ; whilst a slightly acid reaction 

 of the alcohol will produce the opposite effect. The energy 

 of coloration of the fuchsin is often found to become weakened 

 in kept solutions ; 'it may be restored by adding very dilute 

 acetic acid until a marked intensification of the red tint of 

 the mixture is perceived. See 639. 



I have unfortunately not found time to make, as I should 

 have wished, a thorough trial of this now favourite stain. 

 But I have collected a good deal of trustworthy evidence con- 

 cerning it, all my informants concurring in the conclusion 

 that it is really an excellent formula. My able friend Ero- 

 fessor GILSON has tried it with a variety of objects, and has 

 been good enough to give me the following details. The 

 nuclear staining is very sharp and good, the chromatic 

 elements being coloured of a somewhat slaty blue. Cyto- 

 plasm is of a more or less violet or more or less orange red, 

 and caryoplasm is of -the same colour as the cytoplasm, but of 

 a lighter tone. Cell-membranes, nuclear membranes, achro- 

 matic fibrillar structures, the Nebenkern when present in a 

 word, all the denser protoplasmic structures, are stained of 

 the same colour as the hyaloplasm, but darker. The stain 



