2. Treatment with saturated aqueous solution of corrosive sublimate (Muir’s method).
The cover-glass on which the film has been spread, is floated before the latter has time to dry, film downwards on a saturated solution of corrosive sublimate in a watch glass for half an hour. The cover-glass is placed in distilled water and then in alcohol to remove excess of corrosive sublimate, and then stained. A little care is required when washing the film to prevent it sliding bodily off the cover-glass.
3. By drying and passing rapidly through the flame of a Bunsen burner, exactly as in preparing specimens of sputum, &c. (p. [111]). This method is handy for ordinary clinical purposes.
4. By keeping the coverslips at a temperature of about 200° F. (Ehrlich’s method).
Ehrlich uses for this purpose a strip of copper about two inches wide and a foot long which is supported on a retort stand in a horizontal position. One end is heated by a Bunsen’s burner beneath. The point in the copper strip at which the temperature is at boiling point is readily ascertained by dropping a little water on. The point at which a drop of water assumes the spherical state indicates a temperature there of 212° F. The coverslips are placed an inch or two further than this point, and kept there at a temperature of about 200° F. for some hours.
Staining Methods.
Fresh blood may be stained by mixing with Ferrier’s fuchsine solution:—
| Fuchsine | 1 | grm. |
| Distilled water | 150 | c.c. |
Dissolve and add
| Alcohol (80 per cent.) | 50 | c.c. |
| Neutral glycerine | 200 | c.c. |