396 MARGARET R. LEWIS AND WARREN H. LEWIS 



10. The mitochondria become more or less scattered through- 

 out the cytoplasm in an indifferent manner and decrease in size 

 during mitosis. About one-half the quantity of mitochondria 

 is separated into each daughter cell by the plane of division. 

 The individual mitochondria pass over entire into one or the 

 other daughter cell and do not each divide into two halves, each 

 going to one daughter cell, as usually described. 



11. There are some characteristic differences in the mito- 

 chondria of different kinds of cells, but these are not constant 

 enough to be sufficient to distinguish the kinds of cells. 



12. The mitochondria are extremely plastic bodies and often 

 react more rapidly than any other cell structure. They are easily 

 influenced in shape and quantity by varous agents, such as heat, 

 carbon dioxide, acids, alkalies, fat solvents, and potassium per- 

 manganate, or by changes in osmotic pressure of the surround- 

 ing medium. 



13. The mitochondria are stained in these living cells by 

 Janus green but not by nile blue B extra or brilliant cresyl blue 

 2 b except in the dead cell. 



14. Other granules are present in the cells which are not 

 related to mitochondria. 



15. Mitochondria show at times a coincident change in shape 

 with the formation of fat droplets or vacuoles in the cytoplasm, 

 but there is no evidence in these cells of a direct relation between 

 the mitochondria and the formation of either the fat droplets 

 or the vacuoles. 



16. In giant cells the number and quantity of mitochondrial 

 substances is greatly increased above that of the normal cells, 

 somewhat in proportion to the increase in the amount of the 

 cytoplasm and nuclear material. 



The mitochondria are extremely variable bodies, which are 

 continually moving and changing shape in the cytoplasm. There 

 are no definite types of mitochondria, as any one type may change 

 into another. They appear to arise in the cytoplasm and to be 

 used up by cellular activity. They are, in all probability, 

 bodies connected with the metabolic activity of the cell. 



