330 



MANUAL OF HISTOLOGY. 



Fig. 317. Pacinian bodies from the mesen- 

 tery of a cat. a, a nerve with its peri- 

 neurium forming the stalk ; 6, the system 

 of capsules; c, axial canal or internal 

 bulb, within which the nerve tube ends 

 forked. 



ground substance, in which elongated nuclei or cells are imbedded. 

 On the internal surface of these membranes a mosaic marking, like 



epithelium, has been recently remarked 

 by Hoyer after treatment with nitrate of 

 silver. These systems of capsules, fur- 

 ther, are traversed by a scanty vascular 

 network. The individual laminae of which 

 they are composed follow the contour of 

 the whole corpuscle, and are not so thick 

 outwardly as within, where they appear 

 more condensed, and where they sur- 

 round in shorter curves the canal or in- 

 ternal bulb occupying the axis. The 

 latter consists of a soft nucleated connec- 

 tive substance. 



The internal bulb (c) is rounded off at 

 its termination. Its walls, like those of 

 the capsules, are continued at the oppo- 

 site extremity into a stalk (a), by which 

 the Pacinian body is attached like a berry 

 to the nerve. 



This style consists of ordinary longitu- 

 dinally marked connective-tissue, and is 

 formed by the perineurium of the afferent 

 nervous fibre. 



The diameter of the latter is 0-0142- 

 0*0113 mm. and less. It presents the usual medullated appearance, and 

 so reaches the corpuscle, at whose inferior pole it makes its entry into 

 the central canal, occupying the axis of the latter. On entering the 

 central passage the fibre loses its dark border, as is the case in the ter- 

 minal bulb of Krause; it then becomes considerably diminished in size, 

 and comes to an end as a pale terminal filament or axis cylinder of dis- 

 tinctly fibrillated constitution. The latter traverses thus the whole 

 internal bulb, and ends at the roof of the latter (c, above) with a slight 

 button-like swelling. 



Division of the nerve fibre before its entry may occur ; and not unfre- 

 quently do we see, too, the pale terminal fibre splitting into two or three 

 branches, divisions in which the axial canal may also participate. 



Very rarely two nerve fibres are seen to enter the same corpuscle, 

 and terminate singly or doubly in a single internal bulb (Koel- 

 liker). 



Many other variations besides those mentioned here must be passed 

 over. 



That these Pacinian bodies are connected with the sensory-nervous 

 apparatus can hardly be a matter of earnest doubt any longer, since the 

 discoveries of Wagner, Meissner, and Krause. 



REMARKS. These wondrous structures were known even long ago, but they 

 received but little attention. The old German anatomist Vatcr observed, more than 

 a century ago, that the nerves of the skin of the palm of the hand and sole of the 

 foot were studded not unfrequently with small oval swellings, to which he gave the 

 name of papillce nervce. Later on, in the year '30, after having been completely 

 forgotten for some time, they were again discovered by Pacini of Pistoja, and noticed 

 also at the same time in France. They were, however, specially brought into notice 

 through a monograph by Henle and Koelliker, which appeared in the year 1844. 



