MITOCHONDRIA IX PLANT AXD ANIMAL CELLS. 2O5 



Pure acetic acid in half concentration and in full concentra- 

 tion destroys the mitochondria in both tissues. But it must 

 not be thought that acetic acid in small concentrations is to be 

 avoided because I have found that Benda's fluid without acetic 

 acid does not seem to act so well as with acetic acid, in the 

 amount prescribed. 



In other words acetic acid exercises a solvent action on mito- 

 chondria which is the same in plants as in animals and varies 

 with the distance of the cells from the surface and with the 



I- 



FIGS. 5 and 6. Cells from the pea and the pancreas fixed in Zenker's fluid 

 containing 20 per cent, of acetic acid and stained with fuchsin and methyl green. 

 (1,500 diameters.) 



character of the other components of the fixative. There is 

 reason to believe, further, that the resistance of mitochondria 

 in certain young plant cells is less than in old ones, calling to 

 mind the condition which obtains in the spermatogenesis of 

 many animals where the mitochondria in the young cells are 

 more susceptible to acetic acid than in the mature spermatozoa 

 (Regaud, '08, p. 661); which comparison makes the resemblance 

 of plant and animal mitochondria, in this respect, still closer. 



I have attempted to ascertain the experimental error in the 

 study of mitochondria in fixed tissues in plants and animals and 

 to see whether it is the same in both. 



The conditions of the experiment are not so important as the 

 nature of the fixative but they must nevertheless be taken into 

 consideration. Variations in the temperature (under say 46 C.) 

 and the illumination of the tissue prior to fixation do not seem 

 to influence the mitochondria for I have grown peas at room 



