Takahashi, Internodes on Nerve Fibers. 171 



of the III nerve do not yield to the technique which proved fairly- 

 satisfactory in the case of the roots of the IX nerve, so that the 

 technical problem is complicated. In the case of the IX nerve, 

 I used in the first instance solution (D) : 



Osmic acid o . lO per cent, 4 parts 



Chromic acid 0.02 per cent, i part 



The specimen was left in this solution for twenty-four hours, 

 then washed in running water for twenty-four hours, and finally 

 preserved and teased in solution (E). 



50 per cent glycerine. 



This should be renewed several times. 



Later, in place of solution (D), I used solution (F) : 



Osmic acid o. 100 per cent, 5 parts 



Chromic acid 0.025 per cent, I part 



Acetic acid o. 100 per cent, I part 



This gave somewhat better results than solution (D) but none 

 of these solutions acted upon the roots of the III nerve sufficiently 

 well to justify an extended study of its fibers, hence only one III 

 nerve was examined. 



It is fundamental to the following argument, that the treat- 

 ment of the nerves should not materially alter the length or the 

 diameter of the fibers which are to be measured. It was neces- 

 sary therefore to examine the effect of the solutions here employed, 

 and this was done by measuring samples of the nerve as they were 

 passing through the solutions. 



Sixteen samples from different levels along the nerves to the leg 

 were first measured, after having been for two or three hours in 

 solution (A) and then finally measured after treatment in solution 

 (C) when they were ready to be teased. The measurement showed 

 an average loss in length of 3.6 per cent and an average loss in 

 diameter of 12.8 per cent. 



In the case of eight other specimens (four from the III nerve, 

 and four from the IX nerve) examined in the same way, the loss 

 in length was I per cent, and in diameter, 8.6 per cent. 



The loss in length is trifling; that in diameter however seems 

 large. It is probable nevertheless that it is to be mainly credited 

 rather to a diminution in the connective tissue sheath, and to the 



