4:2 NERVOUS SYSTEM. 



complete analogy between the terminations of the sensitive 

 and the motor nerve-fibres, Rouget does not seem to be en- 

 tirely sustained ; for the behavior of the different anatomical 

 elements of the tactile corpuscles when treated by acetic 

 acid, and again when colored with carmine, shows conclu- 

 sively the presence of connective-tissue elements in their 

 outer covering. The observations of Kolliker and others 

 leave no doubt upon this point ; l and as we have already 

 seen in treating of the structure of the nerve-fibres, 2 the 

 changes produced by acetic acid enable us to readily distin- 

 guish the gelatinous nucleated fibres from the elements of 

 connective tissue. While the exact mode of termination 

 of the fibres in the tactile corpuscles is not perfectly clear, 

 we must adopt for the present the views of Kolliker, as the 

 most reasonable and satisfactory. 



Terminal I>ulbs. Under this name, a variety of cor- 

 puscles has lately been described by Krause 3 as existing in 

 the conjunctiva covering the eye and in the semilunar fold, 

 the fioor of the buccal cavity, the tongue, the glans penis, 

 and the clitoris. They bear some analogy to the tactile cor- 

 puscles, but are much smaller and more simple in their struct- 

 ure. They form simply a rounded or oblong enlargement 

 at the ends of the nerves, which is composed of homogeneous 

 matter with an exceedingly delicate investment of connec- 

 tive tissue. They measure from 10 1 00 to -^fa of an inch in 

 diameter. In the parts provided with papillae, they are situ- 

 ated at the summits of the secondary elevations. 



The arrangement of the nerve-fibres in these corpuscles 

 is very simple. One, two, or three medullated fibres pass 

 from the submucous plexus to the corpuscles. The invest- 

 ing sheath of the fibres is here continuous with the con- 

 nective-tissue covering of the corpuscle, and the nerve- 



1 Loc. clt. 2 See page 26. 



8 W. KRAUSE, Die terminalen Korperchen der einfach sensibilen Nerven, Han- 

 nover, 1860, S. 125, et sea. 



