Chap. XV.] I 1 5 



CHAPTER XV. 



PERIPHERAL NERVE-ENDINGS. 



149. IN the preceding chapter the termination of 

 the nerves of common sensation, as isolated primitive 

 fibrillse, and as networks of these, has been described 

 in the epithelium of the skin and mucous mem- 

 branes, and in the anterior epithelium of the cornea. 

 Besides these there are other special terminal organs 

 of sensory nerves, probably concerned in the per- 

 ception of some special quality or quantity of sensory 

 impulses. They are all connected with a medullated 

 nerve-fibre, and are situated, not in the epithelium 

 of the surface, but in the tissue, at greater or 

 lesser depth. Such are the corpuscles of Pacini and 

 Herbst, the end-bulbs of Krause in the tongue and 

 conjunctiva, the genital end-corpuscles or end-bulbs 

 in the external genital organs, the corpuscles of 

 Meissner, or tactile corpuscles, in the papillae of the 

 skin of the volar side of the fingers, the touch-cells of 

 Merkel in the beak and tongue of the duck. 



150. The Pacinian corpuscles. These are 

 also called Yater's corpuscles. They occur in large 

 numbers on the subcutaneous nerve-fibres of the palm 

 of the hand and foot of man, in the mesentery of the 

 cat, along the tibia of the rabbit, in the genital organs 

 of man (corpora cavernosa, prostate). Each corpuscle 

 is oval, more or less pointed, and in some places 

 (palm of the human hand, mesentery of the cat) 

 easily perceptible to the unaided eye, the largest 

 being about -^th of an inch long and -g^th of an 

 inch broad ; in other places they are of microscopic 

 size. Each possesses a stalk, to which it is attached, 



