22 Effie A. Eead 



Arnstein, 1887, confirms Elirlich's work. He saw the olfactory cells 

 with the central thread-like processes passing into the nerve bundle of 

 the submucosa. He claims also to have seen the same thing in the gold 

 chloride preparations of Cisoff and in the isolated osmium preparations 

 of Dogiel. He, like Ehrlich, used methylene blue. 



Ranvier, 1889, found three kinds of cells in batrachians. His general 

 descriptions of these do not differ from those of other investigators. In 

 the frog, salamander, triton, dog and rabbit, Eanvier found a plexus 

 formed from the olfactory fibrils. The central prolongations of the 

 olfactory cells appeared to connect with this plexus. Eanvier claims 

 that the subepithelial plexus described by Exner was above the basal 

 membrane, while the one he found was beyond the basal membrane and 

 hence in the connective tissue. Eanvier does not believe that the fibrils 

 of the olfactory nerve continue directly with the central prolongations 

 of the olfactory cells. He adds that all histologists who pretend to have 

 seen this are victims of a delusion. 



Grassi and Castronovo, 1889, worked on dogs from two to six years 

 old. They demonstrated by the Golgi method an olfactory cell with the 

 peripheral process and with the central end connected with a varicose 

 nerve fiber. This fiber is shown as dividing and subdividing in the 

 connective tissue. In one figure two neighboring cells joined. They 

 were undecided whether the supporting cells were such or whether they 

 were also connected with the nerve, but they state "the connection of 

 these cells with the nerve fiber has never been seen," nor have they 

 seen a connection between this supporting cell and the olfactory cell. In 

 the "limiting zone," at the boundary between the respiratory and 

 olfactory epithelium, they find many varicose nerve fibers which are 

 described as ramifying in the deeper and middle layers of the epithelium. 

 From the many horizontal branches there are some which pass up close 

 to the surface of the epithelium and some which end in the cylindrical 

 olfactory cells. The former may end free, but "this is still not deter- 

 mined." They consider it probable that these fibers are olfactory fibers, 

 Ijut they cannot prove it. 



They also describe for the cylindrical cells of this zone a varicose 

 central process which appears like the nerve fiber. In some cases these 

 have unmistakable signs of nerve fibers, and one figure shows cylindrical 

 cells joined by these branching processes. 



Van GehucMen, 1890, by his work on the rabbit, has confirmed Cajal's 

 work, and says that Cajal's figures are an almost exact representation 



