Takahashi, Internodes on Nerve Fibers. 



■83 



For this purpose it is necessary to determine the average length- 

 ening of the internodes during the period of growth on the nerve 

 fibers taken from Frog 3, Frog 5, and Frog 8. To do this fairly, 

 the diameter classes must be made exactly similar. In addition, 

 due account must be taken of the fact that not only do the inter- 

 nodes increase in length, but the fibers to which they belong, 

 increase at the same time in diameter, and therefore a diameter 

 class of given size in the smaller frog must always be compared 

 with a class of greater diameter in the larger frog. To make this, 

 comparison it is necessary to obtain some notion of the amount 

 of change in diameter which may be expected to occur in the cases 

 w^e are examining. 



Finally, for comparison, it is necessary to determine in the sev- 

 eral frogs compared the proportional lengthening of the nerves 

 to which these fibers belong. 



In the absence of direct observations, we assume that the length- 

 ening of the fibers which pass from the intervertebral foramina 

 to the foot, is proportional to the lengthening of the leg itself. 

 To determine what this is, we proceed as follows: 



Since in the case of the frogs in question, the length of the legs 

 is always a constant fraction of the total length of the frog, it 

 follows that the increase in the length of the legs will be in pro- 

 portion to the increase in the total length of the frog. 



Treating the data in this way, we obtain the results shown in 

 Table 9. 



TABLE 9. 



Showing the relative length of the legs in Frog 3, Frog 5, and Frog 8, based on a 

 comparison of the total lengths of these same frogs. Group (A). Frog 3. taken as 

 the standard. Group (B). Frog 5 taken as the standard. 



Frog. 



Total Length. 



Ratio for the Legs. 



GrcJup f3 



<-^' 11 



Group / 5 

 (B) 18 



1 00.0 

 115.6 



133.7 



From Table 9 it appears that when Frog 3 is taken as the stand- 

 ard in Group (A) the length of the leg in Frog 5, is 15.6 per cent 

 greater, and in Frog 8, i^T^.j per cent greater, while in the second 



