MORPHOLOGICAL AND MICROCHEMICAL VARIA- 

 TIONS IN MITOCHONDRIA IN THE NERVE CELLS 

 OF THE CENTRAL NERVOUS SYSTEM 



NORMAN CLIVE NICHOLSON 



Anatomical Laboratory, Johns Hopkins University 



TWO PLATES 



One of the landmarks in neurology is the demonstration 

 by Nissl in 1885 that different types of nerve cells may be dis- 

 tinguished from one another by the arrangement of the baso- 

 philic material within them. By common consent this baso- 

 philic material came to be called the Nissl substance. This 

 departure in neurology, new at that time, proved extremely 

 fruitful. Investigators flocked to the study of the Nissl sub- 

 stance and through their investigations brought to light many 

 facts of fundamental importance. Since the arrangement of the 

 Nissl substance is more or less specific in different types of cells 

 it was thought that the cells might well be functionally as well as 

 structurally different, just as muscle cells of different structure, 

 gland cells and blood cells of different appearance are assumed 

 to function differently. Thus arose the doctrine of neurone spe- 

 cificity according to which it is supposed that the nervous impulse 

 varies in character with different cell types. 



Through the recent discovery of mitochondria in the cells of 

 the central nervous system it has become possible to attack this 

 old problem from a new point of view and with greatly improved 

 methods of technique. The object of this investigation is to 

 ascertain whether the morphology and microchemical reactions 

 of the mitochondria vary in different types of nerve cells. It is 

 essentially a study of qualitative mitochondrial variation,- and as 

 such it is supplementary to the investigation of Thurlow ('16, 

 p. 253) on quantitative variations. The Nissl substance as we 



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THE AMERICAN JOURNAL OF ANATOMY, VOL. 20, NO. 3 



