276 LECTURE XI. 



what more pointed towards the upper end. Within 

 these layers nuclei can be distinctly seen disposed in 

 regular order, and on following the layers towards the 

 stem of the nerve, they are there observed finally to pass 

 into the perineurium which is in this part very thick. 

 They may therefore be regarded as gigantic developments 

 of the perineurium, which however only enclose a single 

 nerve-fibre. Now on tracing the nerve-fibre itself we 

 observe that its medullated portion usually extends only 

 up to the beginning of the body, when the medulla dis- 

 appears and the axis-cylinder is seen continuing its 

 course alone. It then runs on through the central cavity, 

 and terminates at no great distance from the upper end 

 generally simply, yet often in a little bulbous swelling* 

 and in the mesentery very frequently in a spiral coil. 

 In rare cases it happens that the nerve divides and seve- 

 ral branches pass into the body. But in every case we 

 seem to have before us a mode of termination. What 

 these bodies signify, what office they perform, whether 

 they have anything to do with the function of sensation, 

 or whether their province is to develop any one of the 

 properties of the nervous centres, we are as yet entirely 

 ignorant. 



A certain degree of resemblance to these structures is 

 exhibited by the tactile bodies which have been recently 

 so much the subject of discussion. When the skin and 

 more especially the sensitive part of it is microscopically 

 examined, two sorts of papillae, as was first discovered by 

 Meissner and Hud. Wagner, are distinguished, the one 

 narrower, the other broader, though certainly interme- 

 diate forms are met with (Fig. 83). In the narrow ones 

 we constantly find a simple, in broader ones of the same 

 class a branching, vascular loop, but no nerve. This 



* Quite recently Jacubowitsch has, as he thinks, discovered a ganglion cell in 

 this part. MS. tfkte (if Author. 



