20 SHINKISHI HATAI 



The examination of the two interesting papers just mentioned, 

 suggested several points for further study. It seemed desirable 

 to determine first, how far the results obtained by the simple 

 method of averages would agree with those obtained by the more 

 elaborate statistical treatment of the data; and second, whether 

 or not there is some definite law expressing the relation between 

 the length of the internode and diameter of the fiber on which it 

 occurs, both in different segments of the leg of the same frog, 

 as well as on the same segment of the leg in frogs of different 

 sizes. 



In order to investigate the problems just mentioned, it was 

 necessary to reexamine the original data used in the foregoing 

 researches, and through the efforts of Prof. H. H. Donaldson, 

 I was so fortunate as to get the generous permission of both Boy- 

 cott and Takahashi to use their valuable original data for this 

 investigation, and I wish to express here my thanks to all of these 

 gentlemen. 



METHOD OF TREATING THE DATA 



As has been shown by Boycott and Takahashi, the length of 

 the internode is highly variable, even on the same fiber, as well 

 as on fibers of the same diameter, and therefore in order to get 

 proper mean values in the case of Boycott's records, I have com- 

 bined the data for several frogs, and out of the total of twenty- 

 five frogs, made five groups according to the length of the sciatic 

 nerve as determined by Boycott. 1 



Group 1. Those with a sciatic nerve measuring from 15.5 

 mm. to 17.0 mm. : represented by 2 frogs. 



Group 2. Those with a sciatic nerve measuring from 20.0 

 mm. to 22.5 mm. : represented by 7 frogs. 



Group 3. Those with a sciatic nerve measuring from 24.0 

 mm. to 26.5 mm. : represented by 6 frogs. 



1 The length of the sciatic nerve as defined by Boycott is the distance from 

 the point of emergence from the vertebrae of the upper of the two larger 

 branches of the plexus to the level of the nerve obtained by cutting across the 

 leg through the knee joint when it is in full extension; loc. cit., p. 371. 



