CH. LIT.] 



TACTILE END ORGANS 



721 



a rule, in the papillae in which they are present there are no blood- 

 vessels. 



The peculiar way in which the medullated nerve winds round 

 and round the corpuscle before it enters it is shown in fig. 523. It 

 loses its sheath before it enters into the interior, and then its axis- 



l..... 



a 



FIG. 519. A corpuscle of Herbst, from 

 the tongue of a duck, a, Medullated 

 nerve cut away. (Klein.) 



FIG. 520. End-bulb of Krause. a, Me- 

 dullated nerve-fibre; b, capsule of 

 corpuscle. 



cylinder branches, and the branches after either a straight or con- 

 voluted course terminate within the corpuscle. 



The corpuscles of Grandry (fig. 522) form another variety, and 



FIG. 521. Papillae from the skin of the hand, freed from the cuticle and exhibiting Meissner's corpuscles. 

 A. Simple papilla with four nerve-fibres ; a, tactile corpuscle ; b, nerves with winding fibres c and 

 e. B. Papilla treated with acetic acid ; a, cortical layer with cells and fine elastic filaments ; b, 

 tactile corpuscle with transverse nuclei ; c, entering nerve ; d and e, nerve-fibres winding round 

 the corpuscle, x 350. (Kolliker.) 



have been noticed in the beaks and tongues of birds. They consist 

 of oval or spherical cells, two or more of which compressed vertically 



2 Z 



