Abstract
1. Neuromelanins in the nerve cells of locus caeruleus and substantia nigra of the six human brains are examined histochemically.
2. Neuromelanin stains deep green at pH 4 and 5 in the azure A or methylene blue staining method.
3. By methylation procedure the basophilia of neuromelanins disappears completely in about 48 hours, that of Nissl bodies and glia nuclei in 4 hours.
4. Demethylation following methylation for 48 hours at 60°C. restores basophilia of neuromelanins and is incapable of restoring the same features of Nissl bodies and glia nuclei.
5. Eosinophilic granules in the nerve cells of locus caeruleus and substantia nigra stain good at pH 4.5 in the azure A eosin B staining procedure. These eosinophilic granules are developed much more in the nerve cells of locus caeruleus than those of substantia nigra and also in younger person.
6. The eosinophilia of these granules abolishes at pH 6.5 and 7.5 and is weakened at pH 5.5.
7. By acetylation for 24 hours the eosinophilia of granules abolishes completely.
8. Nitrosation for 24 hours at 25°C. destroys the eosinophilia of the granules completely.
9. Eosinophilic granules appear brilliant red by azo coupling procedure with Fast Garnet GBC.
