Literacy Notices. xcvii 



able to examine many hundred end-bulbs and affirm that I have never 

 certainly seen one nerve-fibre penetrating into the interior of these 

 structures, but only the arrangement described by Lenhossek." 



If these results can be relied upon, the organs of taste must mor- 

 phologically be more widely separated from those of smell than has 

 hitherto been customary. The familiar fact that sapid substances 

 must be present in fluid solution in order to be perceived and that 

 odorous substances, in air-breathing animals at least, must be present 

 in gaseous media, may point to physiological differences in the end-or- 

 gans involving profound structural modifications. But it is more 

 probable that the difference, if difference there be, finds its basis in 

 Organogeny rather than in Physiology. Thus, the processes of the 

 olfactory cells do not connect with any other cells centrally. Prepar- 

 ations recently made by my brother, both by Golgi's method and by 

 the haematoxylin process and figured in this number (Plate XIX, Figs. 

 I, 2, and 3 ; plate XX, Fig. 3) prove conclusively, if additional 

 proof were necessary, that the fibres of the olfactory nerve as they 

 pass into the olfactory tuber break up into terminal brushes (" end- 

 baumchen ") in the glomerules without coming into relations with any 

 cells at this end of their course. In accordance, then, with the cur- 

 rent morphological ideas of nervous structure, 1 the peripheral neuron 

 of the olfactory system would consist of the olfactory ganglion cell in 

 the nasal membrane, its axis-cylinder process which forms one of the 

 constituent parts of the olfactory nerve, ^ and its terminal brush in the 

 glomerule. 



The nerves supplying the taste-bulbs, on the other hand, unques- 

 tionably spring from nerve-cells in the ganglion at the root of their 

 proper nerve-trunk. Since, then, the ganglion cell is at the central 

 end of the fibre, the terminal brush must be sought at the peripheral 

 end; viz. in the " perigemmal fibres." It is obvious that the neuron 

 is complete without the taste-cell ; in fact, the latter would be an in- 

 explicable structure if it were found in direct continuity with the 

 nerve-fibre. 



The views of Lenhossek and Retzius, though concordant with 

 each other and with the most recent morphological ideas of nervous 

 structure, are so different from those commonly held that it is not sur- 



* Compare Obersteiner in Jour. Comp. Neurol., May, 1892, pp. 73-84. 



'According to views current in some quarters the fibre of the olfactory 

 nerve does not run continuously from the nasal epithelium to the glomerule, but 

 consists of several nerve-units in moniliform coanection. This, however, if 

 true, would not materially affect the question now in hand. 



