ON THE LENGTH OF THE INTERNODES IN THE 

 SCIATIC NERVE OF RANA TEMPORARIA (FUSCA) 

 AND RANA PIPIENS: BEING A RE-EXAMINATION 

 BY BIOMETRIC METHODS OF THE DATA STUDIED 

 BY BOYCOTT ('04) AND TAKAHASHI ('08) 



SHINKISHI HATAI 

 Associate in Neurology at The Wistar Institute 



WITH THREE FIGURES 



In 1904 Boycott published an important paper on the length of 

 the internodes under the title "On the number of nodes of Ranvier 

 in different stages of the growth of nerve fibers in the frog." 

 In this work he measured 5338 internodes from twenty-six frogs 

 which ranged in body length from 14.5 mm. to 53.9 mm. Although 

 his observations were limited to the fibers from the thigh taken 

 at the division of the sciatic nerve into the n. tibialis and n. 

 peroneus, they nevertheless give us definite information as to 

 the lengthening of the internodes first in relation to the lengthen- 

 ing of the leg, and second in relation to the increase of the fibers 

 in diameter. 



Four years later (1908) Takahashi published a paper on the 

 same subject under the title "Some conditions which determine the 

 length of the internodes found on the nerve fibers of the leopard 

 frog, Rana pipiens, " and in this investigation he examined several 

 new points. Takahashi's observations were made not only at 

 three different levels in the thigh, but also at levels in the 

 shank and in the foot, as well as on some of the spinal nerve 

 roots. 



He measured altogether 3068 internodes from eight frogs 

 mostly of a larger size than those used by Boycott. The body 

 lengths of Takahashi's specimens ranged from 39.0 mm. to 89.4 

 mm. 



