HISTORY OF MITOCHONDRIAL RESEARCH 15 



The investigations of Regaud, Faure-Fremiet, Lowschin 

 and others on the chemical nature of mitochondria cast a 

 cloud of doubt on the "diverse transformation activities" 

 that had been attributed to mitochondria. Thus, Cowdry 

 ('18), in summing up his criticism on fibril formation, ex- 

 presses the sentiments of cytologists in general when he 

 remarks "that it is somewhat illogical to suppose that sub- 

 stances of such diverse chemical constitution are all formed 

 through the transformation of a single substance, a phospho- 

 lipin, combined perhaps with a small fraction of albumin." 



The influence that these chemical investigations have had 

 on subsequent mitochondrial research has been unfortunate. 

 It is pertinent to analyze minutely the evidence on which the 

 ideas on the chemical constitution of mitochondria have been 

 based. This may be faciUtated by considering the collected 

 evidence as it is given by Cowdry in his critical review of the 

 hterature. After pointing out that three individuals, 

 Regaud, Faure-Fremiet and Lowschin arrived at the same 

 conclusion independently, he tabulates the evidence briefly as 

 follows : 



(1) Mitochondria are almost completely soluble in alcohol, 

 chloroform, ether, and dilute acetic acid. They are rendered in- 

 soluble by chromization. They are not doubly refractile and they 

 do not stain with either Sudan III or Scharlach R. They are only 

 sometimes blackened with osmic acid. 



From the above evidence, apparently, it is assumed that 

 because mitochondria in general are sensitive to these 

 chemicals they all have a like constitution. However, it is 

 well known that mitochondria vary in chemical constitution 

 at different periods in the hfe of the cell. Thus, to quote 

 from another section of Cowdry 's treatise, "It is well known 

 that the mitochondria undergo definite chemical changes in 

 the course of spermatogenesis. Regaud (1910, p. 294) 

 clearly showed that their resistance to acetic acid grows 



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