The olfactory organ is the most primitive of the organs of special sense and the one with the simplest structural organization, and yet it has defied a clear exposition of the way in which it perceives and distinguishes between different odours. The olfactory organ also has a simple structural organization consisting of receptor cells surrounded by supporting cells and overlying a layer of basal cells. Particular areas in relation to the functional anatomy of this organ, such as the fine structure of the olfactory mucosa, the surface fluid and the olfactory pigment are discussed. Perhaps the greatest paradox in olfactory research is that we still do not know the nature of the essential stimulus that constitutes a smell.peer-reviewe
