PACINIAN BODIES. 47 j 



The peripheral termination of nerve-fibres has been 

 always the subject of considerable discussion and doubt. 

 The following appear to be the chief modes of ending of 

 nerve-fibres in the parts they supply : 



I . In fine networks or plexuses ; examples of this are 

 found in the distribution of nerves in muscles, and in 

 mucous and serous membranes. 2. In special terminal 

 organs, called touch-corpuscles (fig. 113), end-bulbs (fig. 114), 

 o.^ Pacinian bodies (figs. 1 36, 1 37)- 3- In cells; as in the eye 

 and internal ear, and some other parts. 4. In free ends ; 

 as from the fine plexuses in muscles, according to Kolliker. 

 5. In muscles, a peculiar termination of nerves in small 

 bodies called motorial end-plates, has been described by 

 llouget and others. These small bodies, varying from 

 5 oVo t irJ-u f an i ncn i n diameter, and placed by different 

 observers outside and inside the sarcolemma, are fixed to 

 the muscular fibres, one for each, and to them the ex- 

 tremity of a minute branch of nerve-fibre is attached. 

 These little plates appear to be formed of an expansion of 

 the end of a nerve-fibre with a small quantity of con- 

 nective tissue. 



The Pacinian bodies or corpuscles (figs. 136 and 137), to 

 which reference has been just made, are little elongated oval 

 bodies, situated on some of the cerebro-spinal and sympa- 

 thetic nerves, especially the cutaneous nerves of the hands 

 and feet ; and on branches of the large sympathetic plexus 

 about the abdominal aorta (Kolliker). They often occur 

 also on the nerves of the mesentery, and are especially 

 well seen in the mesentery of the cat. They are named 

 Pacinian, after their discoverer Pacini. Each corpuscle is 

 attached by a narrow pedicle to the nerve on which it is 

 situated ; it is formed of several concentric layers of fine 

 membrane, with intervening spaces containing fluid ; 

 through its pedicle passes a single nerve-fibre, which, 

 after traversing the several concentric layers and their 

 immediate spaces, enters a central cavity, and, gradually 



