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 " (" Kubin " 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 fur Anilinfabrication 

 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. Mik., 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 haye 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 Pro- 

 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 



