28 SMELL, TASTE, ALLIED SENSES 



other 238 sq. mm. The more recent results of Read 

 (1908), however, show that in man the olfactory fibers 

 spread from the dorsal portion of the olfactory cleft ven- 

 trally over the superior concha almost to its free edge and 

 correspondingly over the septum to about one third its ex- 

 tent. (Fig. 4). The antero-posterior spread of the nerve, 

 according to this author, is about twice 

 that of its ventral distribution on 

 either the concha or the septum; 

 hence the whole area innervated by 

 each olfactory nerve, if spread out 

 flat, would be approximately square 

 in outline and not far from 25 mm. 

 FIG. 4. olfactory cleft to a side, somewhat over twice the 

 ?he m nrsar 8 eptum y ffi" 1 ^ extent ascribed to it by von Brunn. 

 8 To r wl\t b di S c trib^ d ion re o a f 3. Olfactory Epithelium. The olf ac- 



the olfactory nerve. After , -i i i i i n 



Read^ 1908, Plate ii, tory epithelium has been an object or 

 interest to histologists for a long 

 time. As early as 1855 Eckhard stated that in the frog 

 it was composed of two classes of elements, long epithelial 

 cells and nucleated fibers. Which of these served as the 

 endings of the olfactory nerve he was unable to say. In 

 the same year Ecker discovered on the deep face of the 

 olfactory epithelium a third class of cells subsequently 

 called by Krause (1876) basal cells. (Fig. 5.) These 

 three classes of elements were identified in a number of 

 vertebrates and described by Schultze (1856, 1862) who 

 expressed the belief that the nucleated fibers were sense 

 cells and represented the true endings of the olfactory 

 nerve though he was unable to demonstrate a connection 

 between these cells and the nerve. 



It is probable that the connection of the so-called 



