KAHLENBERO — ACTION OF SOLUTIONS ON TASTE. 9 



cases foot-shaped, and that it is highly improbable that they are 

 connected directly with underlying nerves. He finds that nerve- 

 fibres ramify between the cells throughout the entire interior 

 of the taste-bulbs. These nerve-fibres, which lie terms the in- 

 tralobular nerves, are a continuation of underlying nerve-; 

 they traverse the taste-bnib in a general vertical direction, lim- 

 ning out into free end- that are l< cated in many eases near the 

 gustatory pore, in other cases more remote from that opening. 

 Eetzins thinks the so-called taste-cells are true epithelial cells; 

 he regards them as "secondary sense cells,'' similar to the "hair 

 cells'' of the sense of hearing. Retzius then finds more analogy 

 between the organs of taste and hearing than between those of 

 be and smell. Speaking of the sense of taste, he says: 1 



"Es sind meiner Ansicht nach im Geschmacksorgan keine 

 wahren Sinnesnervenzellen vorhanden. Die Xervenzellen des 

 Geschmackser^ans hal en sich ebenfalls, wie im Tastorgan, aus 

 dem Epithel zuriiekgezogen und liegen in den Ganglion des 

 Geschmacksnerven. Das Geschmacksorgan steht also in rnor- 

 phologisch-phylogenetiseher Bezielnmg auf etwa demselben 

 Standpunkt wie das Tastorgan und gewissermassen das Gehor- 

 organ. Die weit gegen das Centralorgan zuriickgetretenen 

 Xervenzellen senden in das peripherische Organ ihren peripher- 

 ischen Fortsatz, welcher unter starker Verastelung mit frei aus- 

 laufenden Spitzen frei und interzellnliir im Epithel endigt; in 

 dem Epithel der Geschmackszwiebeln sind indessen eigenthiim- 

 liche Zellen vorhanden, welche ungefahr, wie die Haarzellen des 

 Gehororgans, als eine Art secundarer Sinneszellen anfgefasst 

 werden konnen." According to this view it is of course not 

 difficult to see why certain portions of the tongue are sensitive 

 to taste and yet possess no taste-bulbs. 



It is generally accepted that sensations of taste are caused by 

 certain irritations of the nerve terminals, — whether we are to 

 regard the "taste-cells" or the "intracellular nerves" as repre- 

 senting these end-organs is perhaps still an open question, though 

 Eetzius appears to have excellent grounds for his opinion. Au- 

 thorities apparently agree that this irritation of the nerves is due 



^oc. Cit., p. 53. 



