A COMPARISON OF MITOCHONDRIA IN PLANT AND 



ANIMAL CELLS. 1 



N. H. COWDRY, 

 ANATOMICAL LABORATORY, JOHNS HOPKINS UNIVERSITY. 



The recent discovery, through the elaboration of new methods 

 of technique, of the wide distribution of mitochondria has at- 

 tracted the attention of many investigators in widely separate 

 fields. Their characteristic form, strongly suggestive of bacteria, 

 is now quite familiar. The technique was devised by anatomists 

 and was applied by them to plant cells. I refer particularly to 

 Meves' ('04, p. 284) work on Nymph&a. But, as might have 

 been expected, these structures did not altogether escape the 

 careful scrutiny of the older botanists, despite their imperfect 

 methods of technique; for Zimmermann ('93, p. 215) certainly 

 observed and described mitochondria in the living hair cells of 

 Momordica elaterium and in the meristem and root tip of Vicia 

 faba. Nevertheless botanists in this country have been slow 

 to study mitochondria notwithstanding the fact that in properly 

 made preparations they constitute a cell organ as conspicuous 

 as the nucleus. 



Unhappily we have deplorably little experimental evidence to 

 lead us to any conclusion as to their functional significance in 

 the cell economy. Our curiosity has been so insistent that we 

 have resorted to less reliable sources of information, one of 

 which is the argument from analogy. It is said that since the 

 mitochondria are found in almost all active cells, their function 

 must be a generalized one which they all possess in common. 

 The validity of this line of reasoning rests entirely upon the 

 resemblance of mitochondria in these different cells. Mito- 

 chondria, however, differ slightly in their solubility in acetic 

 acid and in other respects, and in direct proportion to the extent 

 of variation the above argument loses force. 



1 This work was also carried on at the Marine Biological Laboratory, Woods 

 Hole, Mass., where the Director, Dr. Lillie, very kindly placed a research room at 

 my disposal. It was aided by the Carnegie Institution of Washington. 



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