TERMINATIONS OF THE SENSORY NERVES. 



513 



FIG. 178. Termination of the nerves in the salivary glands (Pfliiger). 

 I, II, branching of the nerves between the glandular cells ; III, termina- 

 tions of the nerves in the nuclei of the cells ; IV, multipolar nerve- 

 cell. 



more or less branching plexus, non-medullated fibres pass directly into the 

 glandular cells and terminate in the nucleoli. The same observer has de- 

 scribed and figured multipolar cells, mixed with the glandular cells, in which 

 some of the nerve-fibres terminate. These, however, are not found in the 

 parotid. These nerve- 

 fibres are regarded as 

 glandular nerves, and 

 they are distinct from 

 the vaso -motor nerves. 



Modes of Termina- 

 tion of the Sensory 

 Nerve*. There un- 

 doubtedly are several 

 modes of termination 

 of the sensory nerves 

 in integument and in 

 mucous membranes, 

 some of which have 

 been quite accurately 

 described, while others 

 are still somewhat un- 

 certain. In the first 

 place, anatomists now 

 recognize three varieties of corpuscular terminations, differing in their 

 structure, probably, according to the different properties connected with 

 sensation, with which the parts are endowed. In addition it is probable 

 that sensory nerves are connected with the hair-follicles, which are so largely 

 distributed throughout the cutaneous surface. There are, also, terminal 

 filaments not connected with any special organs, some of them, perhaps, 

 ending simply in- free extremities, and some connected with epithelium. 

 There are still differences of opinion concerning these various modes of 

 termination of the nerves, but with regard to the terminal corpuscles, these 

 differences relate mainly to anatomical points. It is not proposed, therefore, 

 to enter fully into the discussions upon these questions, but simply to pre- 

 sent what seem to be the most reliable anatomical views. 



Corpuscles of Vater or of Pacini. These bodies were called corpuscles 

 of Pacini, until it was shown that they had been seen about a century and 

 a half ago by Vater. In man, they are oval or egg-shaped and measure -fa 

 to of an inch (1 to 4 mm.) in length. They are always found in the sub- 

 cutaneous layer on the palms of the hands and the soles of the feet; and are 

 most abundant on the palmar surfaces of the fingers and toes, particularly 

 the third phalanges. In the entire hand there are about six hundred, and 

 about the same number on the feet. They are sometimes, but not constantly, 

 found in the following situations : the dorsal surfaces of the hands and feet, 

 on the cutaneous nerves of the arm, the forearm and the neck, the internal 

 pudic nerve, the intercostal nerves, all of the articular nerves of the extremi- 



