[Light microscopy studies on the olfactory epithelium of the deer]

To examine the olfactory epithelium of the roe by the light microscope, the respective nasal region was prepared on the spot right on shooting, stained with a solution of Trypan-Blue, fixed in "Susa" thereafter, and was finally embedded in paraffin by the usual process. Macroscopically already a luxuriant development both of the endo- and ectoturbinalia was to be observed, filling the entire olfactory region of the nasal cavity with numerous folds, convolutions and ramifications. For the purpose of microscopic examination sections from 6 to 10 mum in thickness were made. The border between regio respiratoria and regio olfactoria runs irregularly. Again and again there are patches bare of receptors respectively glandular ones even in the olfactory region. The thickness of the olfactory mucous membrane varies from 140 to 400 mum, the height of the epithelium from 35 to 90 mum. The olfactory area was determined to total approx. 90 cm2 by means of two methods. The distribution of olfactory cells within the epithelium is a very irregular one, their number ranging from 4 to 62 cells per 1000 mum2. Most commonly a density of 24 to 42 cells was encountered. Taking a mean density of 33/1000 mum2 and an overall olfactory area of 90 cm2, the total number of olfactory cells was calculated to run up to 297 million. Sections which turned out well display several olfactory cells entire with pericaryon, dendrite, neck and capitulum with rupturing points of cilia on the latter. Olfactory cells exhibit big dimensional differences. Among other factors their size depends on their relative position within the epithelium and on the density of occurrence. Olfactory cells lying but sporadically within the epithelium mostly possess broad dendrites measuring slightly less in diameter than the pericaryon does, whereas densely situated receptors mainly present thin dendrites and small capitula. Some cell-parts vary independently from each other, some, however, seem to stand in certain relationship to each other. The great differences between individual olfactory cells give rise to the assumption that several cell types or cells of different function respectively are concealed behind it.