Another method is to stain for about ten minutes, and then leave for a minute in Gram’s iodide solution. The sections are then washed in alcohol, dehydrated, clarified in oil of cloves, and mounted in balsam. By these methods the stain is withdrawn except from certain elements, e.g., those undergoing colloid or calcareous degeneration.
A quarter per cent. watery solution is sometimes employed as it stains nucleoli and actively dividing nuclei very brightly, while the rest of the cell is stained faintly. It may be employed to study karyokinesis in the cells of a rapidly growing cancer.
Ehrlich-Biondi stain.—This stain has been much employed for staining specimens of blood, for studying karyokinesis, and for investigations on the supposed parasitic bodies found in cancer cells.
It is prepared by mixing saturated aqueous solutions of the following aniline dyes, slowly and with constant agitation:—
| Solution of Orange G | 100 | parts |
| " Rubin S | 20 | " |
| " Methyl Green OO | 50 | " |
finally add
| Distilled water | 70 | " |
Filter from the copious precipitate which forms. The solution must be made up frequently as it does not keep well.
Sections may be stained rapidly for half an hour or an hour, but better results are obtained by diluting the fluid with twenty volumes of water, and staining all night. Sections should be washed in water and then passed rapidly through absolute alcohol and xylol and mounted in Canada balsam.