THE BEHAVIOR OF MITOCHONDRIA 55 



growing cells than in mature or senile cells, other obser- 

 vations have been made in which there appears to be no 

 such relationship. The observations of Sokoloff ('25) on 

 neoplastic tissue, also, appear to indicate that the number 

 of mitochondria is unrelated to cell division. 



Under abnormal conditions, it is also conceivable that 

 chemical or physical influences may modify the cell in such 

 a manner that the equihbrium is upset, or in other words, 

 the mechanism controlhng mitochondrial growth is de- 

 stroyed. In such an event, the mitochondria would grow 

 and increase so long as food materials are present. Their 

 influence on cell division would, perhaps, be retained, re- 

 sulting in a continuous growth of cells. 



There is a certain amount of evidence that points directly 

 to the probabihty of the presence of such a growth mechan- 

 ism in the cell. Long ago, Engler ('82), Winkler ('99), 

 Ernst ('02), Wigand ('84), and others, observed an up- 

 growth of "bacteria" in intact, but dying algal cells. Some 

 of these observations were made before mitochondria had 

 been discovered. It is quite possible that these "bacteria" 

 were the mitochondria of the normal algal cell which began 

 to grow when vitahty ceased in the host cell. The author 

 has obtained similar results in the mitochondrial culture 

 experiments represented in plate II (p. 38). The tissue 

 represented in figure 14 is a small bit of Uver tissue that had 

 been incubated only two hours. A comparison of this 

 figure with figure 13, which is the normal unincubated tissue 

 from the same animal, reveals at once a decided increase in 

 the number of mitochondria during two hours incubation. 

 It is hardly probable that this increase in mitochondria was 

 dependent upon the food materials present in the medium, 

 but rather that the growth resulted from the food present 

 in the cell which became available as the cell died. While 

 the piece of liver tissue that was incubated was not more 

 than 6 to 10 mm. in diameter, it does not appear probable 



