THE EFFECT OF ACTIVITY ON THE HISTOLOGICAL 

 STRUCTURE OF NERVE CELLS 



R. A. KOCHER 



From the Henry Phipps Psychiatric Clinic, Baltimore,^ and the George WiUinms 



Hooper Fouiidalion for Medical Research, University of 



California, San Francisco 



INTRODUCTION 



The study of the effect of functional activity on the nior])ht)li)»;y 

 of nerve cells has been the subject of numerous investigations 

 in the past. These researches liave covered a considerable range 

 as to kinds of cells studied, degrees of fatigue, and as to methods 

 of treatment of the material. There is almost complete agree- 

 ment on one point, namely, fatigue results in appreciable changes 

 in cell structure. There is, however, the utmost divergence of 

 opinion as to the nature of the clianges, and one who tries to 

 correlate the findings of the different workers in this field is 

 utterly confused. The chief findings relate to" (a) size of cell 

 body and nucleus and (b) amount and distribution of chroniiitic 

 material. While one group of workers concludes that fatigue 

 results in decrease in the size of cell and nucleus (Hodge (1), 

 Van Durme (2), Luxemburg (3), Legendre and Pi^ron (4), Lugaro 

 (5), and Nissl (0) ), another grouj) finds an increase in the size 

 or a change in the nucleus-plasma relation (Crileand Dolley 

 (7), Mann (8), Vas (9) ). Lambert (10) noted no change in 

 the size of cell or nucleus. Increase in chi'omatic substance 

 (hyperchromatism) as the chief result of fatigue has been noted 

 by Nissl. Alost workers (Van Durme (2), Vas (9), Lugaro (5), 

 Mann (8) ) have described a decrease in chromatic material as 



' These experiments were carried out at the suggestion and under tlie direc- 

 tion of Prof. Adolf Meyer, and completed in 1912. The computations were in 

 part made after leaving Baltimore. It g ves me great pleasure to express here 

 my thanks and appreciation to Doctor Meyer for his keen interest in the experi- 

 ments and for many helpful suggestions. 



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THE JOURNAL OF COSfPAR.VTIVK NEVROLOGY, VOL. 2S, NO. 3 



