33 Effie A. Eead 



in the central end. The peripheral process is often irregular and 

 reaches the surface of the epithelium. Its outer edge is bulbous and 

 has numerous cilia-like appendages, the olfactory hairs (Fig. 34). These 

 extend beyond the outer border of the epithelium, free in the nasal 

 cavity. The central process is the axone or olfactory nerve fiber. It is 

 very fine and extends in an undulating course into the underlying con- 

 nective tissue. Only in thick sections could this be followed. These 

 were best seen in the Golgi preparations and in methylene blue material 

 (Figs. 32-34). The sections of gold chloride material showed the 

 axone for a slight distance (Figs. 35, 36). In the dissociated material 

 the axone was generally broken off, but in some preparations axones 

 were found (Figs. 37, 38). 



My work agrees with the results of Van Gehuchten as to the shape 

 of these olfactory cells. He believes the varicosities are due to im- 

 perfect impregnation. I found both varicose fibers and those which 

 were uniform in outline. 



With Max Schultze, I consider these the true olfactory cells. The 

 peripheral process bears the olfactory hairs. The central process is the 

 axone. Early writers described a network for these olfactory axones 

 directly beneath the epithelium as they enter the connective tissue. 

 Eecent work has disproven this, and it is now believed that the axone 

 or olfactory fiber "keeps its unity and independence from the olfactory 

 cell to the olfactory bulb," branching only when it reaches the glo- 

 merulus of the bulb. In none of my work was the branching or 

 anastomosis of an olfactory fiber seen except at this place. Upon 

 reaching the deepest layers of the connective tissue next to the bone 

 these axones or fibers collect into bundles of various sizes and as 

 olfactory nerve bundles extend to and pass through the cribriform plate 

 to the olfactory bulb. 



As has been stated in an earlier part of this paper, almost all authors 

 describe a nerve plexus for these olfactory bundles. This has nothing 

 to do with the network just mentioned, as it concerns only the large 

 nerve trunks and not the individual axones. From the time of Scarpa, 

 1785, to that of Barker, 1904, and Quain, 1906, the olfactory bundles 

 are pictured and described as forming a plexus on the septum and 

 lateral wall of the nose of man. 



If the bone is removed from the orbit and side of the nose (Figs. 13, 

 14), there is certainly a plexiform appearance of the tissue in which 

 the nerve bundles extend. With a consideration of the gross specimen 



