GUSTATORY ORGANS OF MAN AND MAMMALS. 



9 



described spaces, consist of a number varying, according to the 

 size of the bulbs, from fifteen to thirty of long, thin cells, that 

 are arranged like the leaves of a bud. They stand in several 

 closely compressed rows around the axis of the bud. The 

 outermost, which are applied to the wall of the space, and are 

 curved concentrically to it (their concavities being directed 

 inwards), enclose those situated more internally, which are less 

 and less curved as they approach the axis. All gustatory 

 bulbs, it would appear, are composed of at least two principal 

 kinds of cells ; of these, one does not differ very essentially 

 from ordinary epithelial cells, and is not in direct connection 

 with nerves. The cells of the second kind are peculiar, highly 

 differentiated structures, that in all probability are directly 

 continuous with nerves, and are to be regarded as the proper 

 gustatory cells. The former, which may be termed investing 

 cells (Deckzellen), as Loven and Schwalbe suggest, are usually 

 the most numerous, and form the external layers of the bulb ; 

 the second appear to be chiefly situated near the axial region 

 of the bulb. 



Fig. 275. 



Fig. 275. Isolated investing cells, from the gustatory bulbs of the 

 Rabbit. Magnified 600 diameters. 



The investing cells (fig. 275) are long, rather slender, and in 

 general somewhat fusiform structures with an ellipsoidal 

 vesicular nucleus, which is situated either near the centre or 

 towards one end. They consist of clear protoplasm quite free 

 from granules. Towards the gustatory pore they gradually be- 

 come attenuated to a fine point; inferiorly they either diminish 

 but slightly, so that they still remain of considerable breadth 

 where they come into contact with the connective-tissue surface 



