44 NERVOUS SYSTEM. 



form of these corpuscles. Sometimes, however, the terminal 

 bulbs are oblong, and sometimes but a single nerve-fibre 

 penetrates the bulb and terminates in a simple pale filament. 

 The principal forms of the terminal bulbs are shown in Fig. 6. 



General Mode of Termination of the Sensory Nerves. 

 The actual termination of the sensitive nerves upon the gen- 

 eral surface and in mucous membranes is still a question of 

 great obscurity. Though we have arrived at a pretty defi- 

 nite knowledge of the sensitive corpuscles, it must be t re- 

 membered that there is an immense cutaneous and mucous 

 surface in which no corpuscles have as yet been demon- 

 strated ; and it is in these parts, endowed with what we may 

 call general sensibility, as distinguished from the sense of 

 touch, that we have to study the mode of termination of the 

 nerves. 



Kolliker is of the opinion that, in the immense majority 

 of instances, the sensitive nerves terminate in some way in 

 the hair-follicles. 1 If this be true, it will account for the 

 termination of the nerves in by far the greatest portion of 

 the skin, as there are few parts in which hair-follicles do not 

 exist ; but, unfortunately, the exact mode of connection of 

 the nerves with these follicles is not apparent. The fol- 

 lowing is all we know positively of the terminations of the 

 nerves on the general surface : 



Medullated nerve-fibres form a plexus in the deeper lay- 

 ers of the true skin, from which fibres, some pale and nucle- 

 ated and others. medullated, pass to the hair-follicles, divide 

 into branches, penetrate into their interior, and are there lost. 

 A certain number of fibres pass to the non-striated muscu- 

 lar fibres of the skin. A certain number pass to papillae and 

 terminate in tactile corpuscles, and others pass to papillge 

 that have no tactile corpuscles. 



In the mucous membranes, as far as we know, the mode 

 of termination is, in general terms, by a delicate plexus just 



1 Op. dt., p. U4. 



