MITOCHONDRIA VARIATIONS IN NERVE CELLS 341 



ent types of nerve cells of the central nervous system of a mam- 

 mal and the mention of the forms of mitochondria which should, 

 in any experimental study of the nervous system, be regarded 

 as pathognomonic (i.e., net-works, bleb-like swellings, aggluti- 

 nations and vacuolations), are all of interest from a pathologi- 

 cal point of view. The necessity of taking cognizance of mito- 

 chondrial changes is brought home to the clinician through the 

 recent investigations of Goetsch ('16, p. 132) who found that an 

 increase in the mitochondria in the thyi'oid epithelium was asso- 

 ciated with an increase in the activity of the epithelial cells and 

 with the severity of the clinical symptoms of hyperthyroidism 

 in man. 



As nothing has yet been done on the changes in the mitochon- 

 dria in the nerve cells of man in pathological conditions it is quite 

 clear that the following are merely suggestions. 



If Regaud ('11, p. 20) is at all justified in his statement that 

 ''by a still unknown physico-chemical mechanism, the mito- 

 chondria retain a great variety of substances which come in con- 

 tact with the protoplasm, normally as well as accidentally 

 (medicines, poisons, toxins, etc.)" and if the conclusion is war- 

 ranted that the point of action of tetanus toxin on the nerve cell 

 is lipoidal, it is quite possible that a study of mitochondria in 

 the nervous system in tetanus might yield interesting results. 

 At any rate the fact that tetanus toxin is rendered innocuous when 

 mixed with an emulsion of brain pulp (Wassermann and Takaki 

 '98) is evidence that the toxin combines with some component 

 of nerve tissue. Leathes ('10, p. 123) believes that it acts upon 

 a fat which he calls 'cerebrone.' 



There are up to the present no observations on mitochondria 

 in nerve regeneration, although there is evidence from many 

 sources that the mitochondria are dehcate indicators of cell 

 activity, and may reveal interesting facts with regard to the 

 formation of myelin, etc. 



Pathologists have frequently noted that the mitochondria 

 are the first structures in the cell to respond to disturbances in 

 function, which suggests the possibility that a study of them in 

 the nervous system may serve to localize brain lesions which 



