THE PHYSICAL BASIS OF LIFE 



21 



have also made it probable that, in some cases at least, 

 their segregation in the daughter-cells can not be re- 

 garded as a merely passive or mechanical result of mitosis 

 but is determined l)y a more definite and significant rela- 

 tion between these bodies and the centers of division ; for 

 as has recently been demonstrated by Bowen the clion- 



A 





.rr^^s 



ir_Kl« ^ 





B 



FIG. 10 



•Chondriosoiiies in the cells of plants, showing their supposed transformation into 

 plastids (from Guilliermoxd). A-C, from root-tips of barley; C, more enlarged 

 amyloplasts or starch-formers; D, from potato-tuber, with mitochondria and 

 leucoplasts. 



driosomes are sometimes definitely oriented with respect 

 to the centers in a manner that almost suggests that which 

 characterizes the behavior of the chromosomes (Fig, 7). 

 In all this we see surface indications of a more deeply 

 lying ]:)rocess by which the complex cytoplasmic system 

 may jDcrpetuate itself intact from one generation to an- 



