“There are entities which come within the realm of both physicality and psychic expressions which are smaller or subtler than atoms, electrons or protons, and in the psychic realm may be subtler than ectoplasm. For such objects or for such entities I use the term “microvitum”. This microvitum, or in plural microvita, are not of protoplasmic order, and as such they have got little to do with carbon molecules or carbon atoms, which are treated as the initial points or initial stage of life in this universe. So far as physicality is concerned, the position of these microvita is just between ectoplasm and electron, but they are neither ectoplasm nor electron.”
– P.R. Sarkar, “Microvitum, the Mysterious Emanation of Cosmic Factor” (ext. link).