Microglia
Research has discovered dystrophic (defective development) human microglia. "These cells are characterized by abnormalities in their cytoplasmic structure, such as deramified, atrophic, fragmented or unusually tortuous processes, frequently bearing spheroidal or bulbous swellings." The incidence of dystrophic microglia increases with aging. Microglial degeneration and death have been reported in research on Prion disease, Schizophrenia and Alzheimer's disease, indicating that microglial deterioration might be involved in neurodegenerative diseases. A complication of this theory is the fact that it is difficult to distinguish between "activated" and "dystrophic" microglia in the human brain.
Camillo Golgi
An organelle in eukaryotice cells now known as Golgi apparatus or Golgi complex, or sometimes simply as Golgi, was discovered by Camillo Golgi. Golgi modified his black reaction using osmium dichromate solution with which he stained the nerve cells (Purkinje cells) of the cerebellum of an owl. He noticed thread-like networks inside the cells and named them "apparato reticolare interno" (internal reticular apparatus). Recognising them to be unique cellular components, he presented his discovery before the Medical-Surgical Society of Pavia in April 1898. After the same was confirmed by his assistant Emilio Veratti, he published it in the "Bollettino della Società medico-chirurgica di Pavia". However, most scientists disputed his discovery as nothing but a staining artefact. Their microscopes were not powerful enough to identify the organelles. By the 1930s, Golgi's description was largely rejected. It was only firmly established after 50 years of its discovery, when electron microscopes were developed.