10 S. B. VINCENT 



The dermal plexus and the plexus of the outer root sheath. All 

 over the dermal sheath of the follicle is a plexus of fine varicose 

 fibers and a very similar one is seen on the surface of the outer 

 root sheath. As one looks down on the follicle it appears to be 

 covered with a fine network of nerves. It is difficult to say 

 whether the fibers really anastomose or not, but in many cases 

 where they can be followed they seem to lie over or under one 

 another. They grow finer and finer with repeated divisions and 

 when the end can be seen it is usually a simple fiber, or what is 

 more common the fibril ends with one of the varicosities with 

 which, as has been said before, it is studded. The fibers have 

 very much the appearance of sympathetic fibers and some of 

 them can be seen branching from nerves which accompany arte- 

 ries. Botezat's opinion ('07) that these plexuses have to do with 

 the nourishment of the follicle seems the true one. Since our 

 interest is in the sensory nerve, these will not be discussed further 

 and no attempt will be made to describe the motor nerves which 

 may be seen going to the muscles of the follicle. 



Nerves on trdbeculae. Of the same nature are the nerves in the 

 connective tissue strands of the lower sinus. The trabeculae 

 which fill the large cavity of the blood sinus below the ringwulst 

 furnish bridges for crossing fibers (fig. 8). Some of these sur- 

 round the walls of the arteries which they accompany and others 

 resemble these so much that, though their immediate connection 

 with any blood vessel cannot be seen, one may infer them to be 

 from the sympathetic system. Still others detach themselves 

 from the trunk of the main nerve coming from below and cross 

 singly on these pathways. The latter are for the most part 

 sensory nerves destined for the lower part of the follicle and 

 immediately turn back in that direction. 



Nerves in the papilla. There are nerves forming a rich plexus 

 within the papilla. They are usually varicose and sometimes 

 can be seen running with the arteries. They often reach a con- 

 siderable height in the medulla of the hair (fig. 10). 



Bonnet was not the only one who thought the papilla with- 

 out nerves (78, p. 390), but Retzius •('92-'96), Orru ('94) 

 and others described nerves in this place. Ostroumow thought 



