464: HANDBOOK OF PHYSIOLOGY. 



velopment of the primitive sheaths of the nerve-fibres, entering the 

 papillae. Others, however, believe that, instead of thus consisting of a 

 homogeneous mass of connective tissue, they are special and peculiar 

 bodies of laminated structure, directly concerned in the sense of touch. 

 They do not occur in all the papillae of the parts where they are found, 

 and, as a rule, in the papillae in which they are present there are no 

 blood-vessels. Since these bodies in which the nerve-fibres end are only 

 met with in the papillae of highly sensitive parts, it is inferred that they 

 are specially concerned in the sense of touch, yet their absence from the 

 papillae of other tactile parts shows that they are not essential to this 

 sense. 



The peculiar way in which the medullated nerve winds round and 

 round the corpuscle before it enters it is shown in Fig. 325. 



It loses its sheath before it enters into the interior, and then its axis- 

 cylinder branches, and the branches coil around the corpuscle (Fig. 

 325), anastomosing with one another and ending in pear-shaped enlarge- 

 ments. 



(5.) The corpuscles of Grandry (Fig. 324), form another variety, and 

 have been noticed in the beaks and tongues of birds . They consist of 

 corpuscles oval or spherical, contained within a nucleated sheath, and 

 containing several cells, two or more compressed vertically. The cells 

 are granular and transparent, with a nucleus. The nerve enters on one 

 side, and laying aside its medullary sheath, terminates in or between the 

 cells. 



(6.) Nerve terminations, probably sensory in function, are found in 

 iutermuscular tissue (Figs. 326, 327), and also in tendon. The former 

 are reticulated end plates, and the latter are something like small Paci- 

 nian corpuscles (Fig. 328). 



(7.) In addition to the special end organs, sensory fibres may termi- 

 nate in plexuses, as in the sub-epithelial and the mtra-epithelial plexus 

 of the cornea. 



B. Of Nerves of Special Sense. The terminations of the nerves 

 of special sense will be considered in the Chapter on the Special Senses. 



0. Of Motor Nerves. The terminations of nerves in muscle, both 

 striped and unstriped, have been already described, p. 398. 



D. Of Secretory Nerves. The ending of nerves in the cells of the 

 salivary glands has been described by Pfliiger, and has been already 

 alluded to. 



III. GENERAL PLAN OP THE CONSTRUCTION OF THE NERVOUS 



SYSTEM. 



The Nervous System is made up of two portions or systems, the (I.) 

 Cerebro-spinal, and the (II.) Sympathetic. 



(I.) The Cerebro-spinal System includes the Brain including 



