Granules with affinity for silver—silver granules—have been described at various times in pathologic and neuropathologic literature. Thus, Jahnel1 in 1919 spoke of dark granules which were scattered in the tissues, singly or in connection with threadlike fragments of Spirochaeta pallida. He stated that Levaditi and his co-workers described ultramicroscopic granules which, like Jahnel's granules, represented modified spirochetes. Jahnel saw the granules only in areas densely invaded by spirochetes, but never in areas free from them.
Kon2 observed silver granules in practically every tissue and organ of the body, including the brain. Fine and coarse black or brown granules were present also in the cytoplasm of the ganglion cells, but not in their nuclei. In the brain of a rabbit "blackish" granules were present in the cortex, optic thalamus, corpora quadrigemina, cerebellum, pons, medulla, spinal cord and sympathetic and spinal ganglia. In the nuclei of the hypoglossal nerve, "dotlike"
HASSIN GB, DIAMOND IB. "SILVER CELLS" AND "SPIROCHETE-LIKE" FORMATIONSIN MULTIPLE SCLEROSIS AND OTHER DISEASES OF THE CENTRAL NERVOUS SYSTEM. Arch NeurPsych. 1939;41(3):471–483. doi:10.1001/archneurpsyc.1939.02270150045003