MITOCHONDRIA IN TISSUE CULTURES 347 



were clearly seen in the living cell as long rods and threads 

 rapidly disappeared. Brunn ('84) found that the Eberth bodies, 

 which have since been shown to be mitochondria, are dissolved 

 by acetic acid. Duesberg ('11) states the fact that they are 

 destroyed by acetic acid to be one of the criteria for mitochon- 

 dria. Prolonged fixation in osmic acid after the osmic vapor 

 has already fixed the preparation did not cause any distortion 

 of the nucleus or the cytoplasmic structures. The mitochondria 

 became somewhat blackened and the fat globules were first 

 yellow-brown and later became a dark brown. Even after a 

 month no change appeared in the cytoplasm which in any way 

 indicated the presence of a canilicular apparatus as was found 

 in certain other cells by Kopsch ('02), Sjovall ('06), and Cowdry 

 ('12). 



A careful study of the living cell together with a study of the 

 effect of various fixatives shows that while the mitochondria 

 are only successfully fixed by osmic acid, they are by no means 

 artifacts due to osmic acid fixation. 



MITOCHONDRIA 



The mitochondria are always present in the living cells of 

 the tissue cultures and after some experience can be easily recog- 

 nized. They are never as conspicuous, however, as the fat 

 globules or the nucleus. The mitochondria are slightly refract- 

 ive bodies which vary greatly in shape, size, and position. 

 In the living cell these bodies are never quiet, but are contin- 

 ually changing in shape, size, and position. Often as many as 

 fifteen or twenty shapes may be exhibited by a single mitochon- 

 drium within as many minutes (fig. 3). This extreme plasticity 

 of the mitochondria is a very important characteristic and was 

 shown in every preparation examined. It is certainly a feature 

 which must be reckoned with in any attempt to classify or to 

 analyze their behavior from fixed material. 



The chaotic condition of the literature in respect to the ter- 

 minology and criteria for mitochondria and other cytoplasmic 

 bodies renders it difficult often to correlate our findings with 



