ON THE NUMBER AND ON THE RELATION BE- 

 TWEEN DIAMETER AND DISTRIBUTION OF 

 THE NERVE FIBERS INNERVATING THE LEG 

 OF THE FROG, RANA VIRESCENS BRACHY- 

 CEPHALA, COPE. 



By Elizabeth Hopkins Dunn, M. D. 



(From the Neurological Laboratory of the University of Chicago.) 

 With two figures in the text. 



CONTENTS. Page 



Summary. . . ..,-.. 298 



Introduction. ....... 299 



Section I. Gross Anatomy of the Muscular and Cutaneous Nerves 



Supplying the Thigh and the Shank . . 299 



A. Comparison of Rana virescens with Rana esculenta and 



Rana temporaria ..... 300 



1. Variations appearing in successive dissections of 



Rana virescens ... . 303 



2. Differences between Rana virescens and the standard 



furnished by Rana esculenta . . 304 

 Section II. Number and Diameter of the Nerve Fibers innervat- 

 ing the Thigh, Shank and Foot . . . 305 



A. Introduction. . . . . . 305 



1. Levels at which observations were made . . 306 



2. Methods of observation .... 308 



a. Enutneration ..... 308 



b. Determination of the Average for each fiber . 309 



c. Determination of the average areas oi .the largest 



fibers .... 309 



B. Number of Nerve Fibers. 310 



1. Enumerations at the various levels of the sciatic and 



crural nerves, and of the thigh and shank branches 



at their points of separation from the main trunks 310 



2. Significance of the excess of the observed over the cal- 



culated number of fibers to both thigh and shank 313 



