474 



HISTORY OF THE HUMAN BODY 



an oval core, upon which the nerve fibers are wound in an 

 irregular branching spiral. Certain types, on the other hand, 

 seem to possess no epidermal elements, as in Krause's cor- 

 puscles (Fig 1 . 128, d), which consist of a globular snarl of 

 nerve fibers like a capillary glomerulus, enclosed within a thin 

 covering of connective tissue. In still another type, shown by 

 Grandry's corpuscles (Fig. 128, e), the nerve terminus is en- 

 closed between two large epidermal cells which seem to pro- 



b 



. 



FIG. 128. Various endings of sensory nerves. 



(a) Free nerve ending. (b) Merkel's corpuscles. (c) Meissner's corpuscle. 

 (d) Krause's corpuscle; (e) Grandry's corpuscle. (f) Pacini's corpuscle. 



duce the stimulus by transmitting any pressure to which they 

 are subjected. This last principle is employed in a more 

 elaborate manner in Pacini's corpuscles, perhaps the largest 

 and most complex of the series, where the nerve terminus is 

 enclosed first by a layer of epithelial cells, then by a series 

 of consecutive lamellae of connective tissue, something like the 

 coats of an onion, and finally by an external connective tissue 

 wrapping, the continuation of the nerve sheath or neurilemma. 



