2. In the practical application of the triacid fluid, particular care must be taken, as M. Heidenhain first shewed, that the dyes are chemically pure[6]. Formerly granules, apparently basophil, were frequently observed in the white blood corpuscles, particularly in the region of the nucleus. They were not recognised, even by practised observers (e.g. Neusser) as artificial, but were regarded as preformed, and were described as perinuclear forms. Since the employment of pure dyes these appearances, whose meaning for a long time puzzled us, are but seldom seen.
Saturated watery solutions of the three dyes are first prepared, and cleared by standing for some considerable time. The following mixture is now made:
| 13-14 c.c. | Orange-g. solution |
| 6-7 c.c. | Acid fuchsin solution |
| 15 c.c. | Aqu. dest. |
| 15 c.c. | Alcohol |
| 12.5 c.c. | Methyl green |
| 10 c.c. | Alcohol |
| 10 c.c. | Glycerine |
These fluids are measured in the above-mentioned order, with the same measuring glass; and from the addition of methyl green onwards the fluid is thoroughly shaken. The solution can be used at once, and keeps indefinitely. The staining of the blood specimen in triacid requires only a little fixation, cp. page 35. The stain is completed in five minutes at most.
The nuclei are greenish, the red blood corpuscles orange, the acidophil granulation copper red, the neutrophil violet. The mast cells stand out by "negative staining" as peculiar bright, almost white cells, with nuclei of a pale green colour.
The triacid stain is very convenient. It is much to be recommended for good general preparations; it is indispensable in all cases where the study of the neutrophil granulations is concerned.
3. Basic double staining. Saturated, watery methyl-green solution is mixed with alcoholic fuchsin.
The stain, which only requires a small fixation, is completed in a few minutes, and colours the nuclei green, the red blood corpuscles red, the protoplasm of the leucocytes fuchsin colour. It is therefore specially suited for demonstration preparations of lymphatic leukæmia.
4. Eosin-methylene blue mixtures, for example Chenzinsky's fluid:
| Concentrated watery methylene blue solution | 40 c.c. |
| 1/2% eosin solution in 70% alcohol | 20 c.c. |
| Aqua dest. | 40 c.c. |