Biological Papers. 



841 



sent and soon dies without it. Also, centrosome arises by division 

 of centrosome, and plastid by division of plastid. The chloro- 

 plastids and chromoplastids are derived from leucoplastids. Evi- 

 dently these forms of protoplasm would each occupy less and less 

 space by self-division did they not absorb and assimilate nourish- 

 ment and become more and more inactive did they no.t continuously 

 release fresh supplies of energy from energy-containing foods for 



fii&tu. 



i-r 



the activities of the protoplasm ; but all this is merely additional 

 proof that in studying these forms of protoplasm we are studying 

 the various manifestations of a power that is something more than 

 that possessed by matter and an intelligence that is greater than 

 that manifested by unharnessed energy. 



The two spirem threads, shown in A, soon move together, 

 chromomere of one moving to a chromomere of the other.* The 

 result is a single spirem shown in B. This conjugation persists 

 in the case of Liliut/i canadense for from two or three days to a 

 week. What happens while the two threads are in conjugation, 

 what influences cross from one chromomere to the other, no one 

 knows. The best observers believe that the conjugating chromo- 

 meres of the two spirems come from different parents, those of one 

 spirem from one parent and those of the other spirem from the 

 other. During the lifetime of the individual producing the mother 

 germ-cell, the chromomeres remained distinct, and all the cells of 

 her body were under the control of those chromomeres whose life 

 powers were dominant, according to the Mendelian law. 



After close union for several days the spirem splits, as shown in 

 C, but no one knows whether the division plane corresponds to the 



* This description follows somewhat closely that of chromosome reduction in Liliuni ca7ia- 

 dense by Charles E. Allen. University of Wisconsin, in Botanical Gazette, June, 1904; and of 

 Strasburger and Lang. 1908. 



