152 FREDERICK TUOKERMAN. 



before entering the " nerve-cushion " lose their medullary 

 substance and neurilemma. 



In 1869, Beale (3) redescribed the epithelium of the papillae 

 of the frog, and reiterated his disbelief in the existence of 

 structural continuity between nerve-fibres and epithelial cells. 

 He figured fine nerve-fibres ramifying in the connective tissue 

 of the simple papillae, and connected with them oval-shaped 

 masses of germinal matter or nuclei, formerly supposed to be 

 connective tissue. He believed in a connection between the 

 cells upon the summit of the fungiform papilla and the nerve- 

 fibres in its axis, but did not consider the former epithelial in 

 structure. He figured a nervous plexus containing nuclei at 

 the top of the papilla, the fibres of which are derived from the 

 nerves in its axis, and from which fine fibres may be traced 

 into the special organ composed of " epithelial-like " cells. 

 He found that the bundle of nerve-fibres distributed to a 

 papilla always divides into two, which pursue opposite direc- 

 tions ; this division taking place either at the base of the 

 papilla or at some distance from it. 



In 1869, Maddox (29) regarded the fungiform papillae as the 

 chief organs of taste in the frog, and described the nerves of 

 taste as possessing terminal organs consisting of nerve matter. 



In 1867, Szabadfoldy (43) described the nerves of taste as 

 terminating in mammals in pear-shaped bodies lying in the 

 mucous membrane of the tongue. Two years later Letzerich 

 (22) called attention to a peculiar way in which these nerves 

 end in the papillae of the cat, ox, and weazel. In neither case 

 have the results reached by these observers been verified. 



In 1867, Loven (27) described the taste-bulbs (Geschmacks- 

 zwiebeln) or taste-buds (Geschmacksknospen) of mammals. He 

 studied them in the circumvallate papillae of the cat, rabbit, 

 pig, sheep, calf, dog, horse, and man, and found them to con- 

 sist of central and peripheral cells. The outer or cover-cells, 

 for support and protection ; the inner or taste-cells, bearing a 

 central and peripheral process, the former being continuous 

 with a nerve- fibril, the latter terminating in a delicate hair-like 

 extremity which projects a short distance beyond the opening 



