282 GERM-CELL CYCLE IN ANIMALS 



cell described by the same investigators. "The 

 mitochondria are almost never at rest, but are con- 

 tinually changing their position and also their shape. 

 The changes in shape are truly remarkable, not only 

 in the great variety of forms, but also in the rapidity 

 with which they change from one form to another. A 

 single mitochondrium may bend back and forth 

 with a somewhat undulatory movement, or thicken 

 at one end and thin out at the other with an appear- 

 ance almost like that of pulsation, repeating this 

 process many times. Again, a single mitochondrium 

 sometimes twists and turns rapidly as though 

 attached at one end, like the lashing of a flagellum, 

 then suddenly moves off to another position in the 

 cytoplasm as though some tension had been re- 

 leased." Mitochondria may also be stained intra 

 vitam, especially with dahlia violet and Janus green. 

 Most of the fixing solutions ordinarily used for cy to- 

 logical purposes destroy the mitochondria. The 

 methods which seem to give the best results have 

 osmic acid or formalin as a basis, such as those de- 

 vised by Altmann (see Lee, 1905, p. 43), Benda 

 (Lee, 1905, p. 223), Meves (1908), and Regaud 

 (1908, p. 661). Benda (1903) claimed that all 

 cellular structures which stained violet by his method 

 were of a mitochondrial nature ; but this has not been 

 found to hold true. Undoubtedly the many bodies 

 which have been discovered in cells are of several 

 sorts, and only by a thorough study of their staining 

 qualities, morphological aspects, and biological roles 

 can they be identified. Benda's crystal violet 



