1122 



forearm, skin of the lips, and the mucous membrane of the tip of the tongue, the 

 palpebral conjunctiva, and the skin of the nipple. They are not found in all the 

 papillse ; but from their existence in those parts in which the skin is highly sensi- 



Nerve-fibres. 



Terminal ramifications 

 of axis-cylinder. 



FIG. 659. Nerve-ending of Ruffini. (After A. Ruffini, Arch. ital. de Biol., Turin, t. xxi. 1894.) 



tive, it is probable that they are specially concerned in the sense of touch, though 

 their absence from the papillae of other tactile parts shows that they are not essen- 

 tial to this sense. 



Ruffini has described a special variety of nerve-ending in the subcutaneous 

 tissue of the human finger (Fig. 659). These are usually known as Ruffini 's 



endings. They are principally situated at the 

 junction of the corium with the subcutaneous tis- 

 sue ; they are oval in shape, and consist of a 

 strong connective- tissue sheath, inside which the 

 nerve-fibre divides into numerous branches, which 

 show varicosities and end in small free knobs. 

 They resemble the corpuscles of Golgi. 



The Pacinian corpuscles 1 (Fig. 660) are found 

 in the human subject chiefly on the nerves of 

 the palm of the hand and sole of the foot 

 and in the genital organs of both sexes, lying 

 in the subcutaneous tissue ; but they have also 

 been described as connected with the nerves of 

 the joints, and in some other situations, as the 

 mesentery of the cat and along the tibia of the 

 rabbit. Each of these corpuscles is attached to 

 and encloses the termination of a single nerve- 

 fibre. The corpuscle, which is perfectly visible 

 to the naked eye (and which can be most easily 

 demonstrated in the mesentery of a cat), consists 

 of a number of lamellae or capsules, arranged more 

 or less concentrically around a central clear space, 

 in which the nerve-fibre is contained. Each lamella 

 is composed of bundles of fine connective-tissue 

 fibres, and is lined on its inner surface by a single 

 layer of cells. The central clear space, which is 

 elongated or cylindrical in shape, is filled with a 

 transparent material, in the middle of which is the 

 single medullated fibre, which traverses the space 

 to near its distal extremity. Here it terminates 

 in a rounded knob or end, sometimes bifurcating 

 previously, in which case each branch has a sim- 

 ilar arrangement. Todd and Bowman have de- 

 scribed minute arteries as entering by the sides of the nerves and forming capil- 

 lary loops in the intercapsular spaces, and even penetrating into the central space. 

 1 Often called in Czerman anatomical works " corpuscles of Vater." 



FIG. 660. Pacinian corpuscle, with its 

 system of capsules and central cavity, 

 a. Arterial twig, ending in capillaries, 

 which form loops in some of the inter- 

 capsular spaces, and one penetrates to 

 the central capsule. 6. The fibrous tissue 

 of the stalk prolonged from the perineu- 

 rium. n. Nerve-tube advancing to the 

 central capsule, there losing it's white 

 matter, and stretching along the axis to 

 the opposite end, where it is fixed by a 

 tubercular enlargement. 



