SENSORY NERVE-ENDINGS. 



vicinity of the joints, in tendons, in the muscle-sheaths, in the periosteum, 

 in the tunica propria of the serous membranes (the parietal peritoneum, 

 the mesentery and the pleura), in the neighborhood of the pancreas and of 

 the oviduct. They are particularly large in the mesentery of the cat, where 



they may be detected readily 

 oval pearly bodies, sometimes 

 The most conspicuous 

 puscle is the robust capsule 

 the entire bulk of the body 

 to three dozen thin concentric 

 lae. The opposed surfaces of 

 rated by a single layer of flat 

 tissue cells, whose nuclei ap- 

 enings along the concentric 

 vidual lamellae. The axis of 

 the Pacinian corpuscle is occu- 

 pied by a core of semifluid 

 substance, the inner bulb, in 

 which the naked axis-cylinder 

 is embedded. On joining the 

 proximal pole of the corpuscle, 

 the fibrous (Henle's) sheath 

 of the nerve-fibre blends with 

 the lamellae of the capsule, 

 while the medullary coat is 

 retained during the somewhat 

 tortuous path of the fibre 

 through the capsule as far as 



with the unaided eye as 

 2-3 mm. in length, 

 part of the Pacinian cor- 

 that contributes almost 

 and consists of from one 

 connective tissue lamel- 

 the lamellae are sepa- 

 plate-like connective 

 pear as fusiform thick- 

 lines marking the indi- 



FIG. 117. Vater-Pacinian corpuscles from skin of finger? 

 A , longitudinal, B, transverse section ; n, nerve entering 

 capsule to reach inner bulb. X H5- 



the core. At this point the 

 remaining envelope of the nerve-fibre disappears, the subsequent part of its 

 course, through the inner bulb, being as the naked axis-cylinder. At a 

 variable distance from, but often just before gaining, the distal pole of the 

 core, the axis-cylinder divides into from two to four branches, each of 

 which terminates in a slightly expanded end-knob. Sometimes shortly after 

 penetrating the capsule, the nerve-fibre splits into two or more axis-cylinders, 

 which then share in common the envelope of semifluid axial substance. 



The Golgi-Mazzoni corpuscles, found in the corium of the skin on 

 the finger-bulbs and on the external genital organs, in the conjunctiva, and 

 in the peritoneum, are modifications of the ordinary Pacinian corpuscles. 

 They differ from the latter in being smaller and in possessing fewer lamellae, 

 a relatively larger core and a more branched axis-cylinder. 



Mention may be made of the corpuscles of Hcrbst, which, on account 

 of their accessibility, are frequent objects of study. They are found in the 

 velvety skin covering the bill and in the tongue of water-fowl and are asso- 

 ciated with the Grandry's corpuscles already mentioned. They closely 

 resemble the Pacinian bodies of mammals, but differ in being smaller, rela- 

 tively broader, and in exhibiting a double row of oval nuclei within the inner 

 bulb and around the axis-cylinder. 



Neuromuscular Endings. In addition to sensory nerve-fibres which 

 end between the muscle fibres as free terminal fibrils, voluntary muscle is 

 provided with special sensory end-organs, long known as muscle-spindles^ 

 probably concerned in transmitting impulses that afford impressions as to 

 tension or ' ' muscle-sense. ' ' The neuromuscular endings lie within the con- 



