THE COMPARATIVE DISTRIBUTION OF MITO- 

 CHONDRIA IN SPINAL GANGLION CELLS . 

 OF VERTEBRATES^ 



E. V. COWDRY 



Department of Anatomy, Johns Hopkins University 



FOURTEEN FIGURES (THREE PLATES) 



CONTENTS 



Introduction 1 



Literature 2 



Material and methods •. • ■ • 9 



Observations 1 1 



Discussion 16 



Results 21 



INTRODUCTION 



This paper constitutes part of a program of research, outUned 

 some years ago, the object of which is to lay a sound foundation 

 for the study of functional changes in nerve cells. In the first 

 place, I confined my attention to a single tj^pe of nerve cell and 

 brought the most refined methods of general cytology to bear 

 upon an analysis of its cytoplasmic constituents ('12); I then 

 began a study of the same cytoplasmic constituents in devel- 

 opment, paying particular attention to the histogenesis of neuro- 

 fibrils ('14 a); and I now wish to present some observations, 

 based upon a study of the comparative distribution of nerve 

 cell granulations, which I believe throw some light on the 

 structural relations and physiological significance of both the 

 mitochondria and the Nissl substance. They indicate that 

 mitochondria are fundamental constituents of spinal ganglion 

 cells, which probably play a part in metabolism; and that the 

 Nissl substance occurs in living spinal ganglion cells as a dif- 



' Aided by the Carnegie Institution. 



THE AMERICAN JOURNAL OF ANATOMY, VOL. 17, NO. 1 

 NOVEMBER, 1914 



