THE PERIPHERAL NERVE-ENDINGS. 



once be considered. These structures, widely distributed in man 

 and mammals, are elliptical, semi-transparent bodies, some 23 mm. 

 long and half as broad, which occur along the nerves supplying the 

 skin, especially of the hands and feet, the external genitalia, the 

 joints of the extremities, the periosteum of certain bones, the peri- 

 toneum, and many other localities. Of the three component parts 

 of the typical end-bulb, the capsule has undergone the greatest 

 development in the corpuscles of Vater, being composed of 25-50 

 concentric connective-tissue lamellae, each of which possesses an 

 outer transverse and an inner longitudinal layer of fibres, and is lined 



by a single layer of endothelial 



FIG. 107. cells ; the nuclei of these plates 



are seen in profile throughout the 

 capsule. The individual lamellae 



Thp 



Corpuscle of Vater, or Pacinian body, from the 

 mesentery of cat : N, nerve-fibre enclosed wiihin 

 the perineurial sheath, with which the lamellae 

 of the capsule (Kfis) are connected ; K , nuclei of 

 the endothelial plates of same ; Jk, inner bulb 

 enclosing the axis-cylinder (fix), which at Thp di- 

 vides into the terminal branches. (After Rnnvier.) 



til- 



Herbst's corpuscle from the bill of duck : m, 

 medullated nerve-fibre passing into the interior 

 of the capsule, where the axis-cylinder lies within 

 the granular inner bulb (z ) surrounded by a row 

 of nuclei; the spindle nuclei appear between 

 the outer and less closely placed lamellae of the 

 capsule. 



are separated by a clear serous fluid, which is largest in amount be- 

 tween the peripheral layers, since the lamellae immediately surround- 

 ing the inner bulb are thinner and more closely placed. The lamellae 

 of the capsule are often united along a longitudinal area the intra- 

 capsular ligament which corresponds to the course by which the 

 nerve-fibre gains entrance to the inner bulb ; occasional trabeculae 



