42 



R. T. YOUNG 



the two lines being only ten. Further reference to this result will be 

 made in the general discussion. 



Experiment 8 (figs. VIII and Villa) 



On 2/22 line VIII was branched off from line II and carried with- 

 out change of slide in beef extract until 3/1. On this date the line 

 was transferred to a fresh hay infusion on another slide, and carried, 





with infrequent slide changes, in the same culture until its death on 

 5/8. 



Several descendants of line VIII were sowed in the culture jar and a 

 weak culture developed, which however died previous to 4/19, for 

 what cause I cannot say. Endomixis occurred in line II on an aver- 

 age of once in thirty-five generations, while in line VIII it occurred 

 once in eighteen and one-half generations, counting from the appear- 

 ance of the first endomixis on 2/25. It is noteworthy that between this 

 and the next endomixis on 4/10 a period of thirty generations ensued, 



