44 R. T. YOUNG 



kindly prepared for me by Dr. W. W. Hanford of the State Pub- 

 lic Health Laboratory, and was ammonia free at the outset of 

 the experiments, while at their close several weeks later it con- 

 tained only a trace. It was applied in gradually increasing 

 amounts, starting with mixtures varying from one drop of dis- 

 tilled water to one of beef extract solution, to one drop of the 

 former to five of the latter, and increasing up to pure water. 



Experiment 10 (figs. X, Xa and b) 



In this experiment line X was carried in beef extract for one hun- 

 dred and thirty-one generations from 1/25 to 5/7 with infrequent 

 slide changes. On 3/30 two lines (Xa and b) were branched off from 

 X and carried without change of slide until 4/11. The culture fluid 

 used at the outset of the experiment was a 5 : 1 mixture of beef ex- 

 tract solution and distilled water. This was gradually diluted to 

 pure distilled water on 4/11 when both lines died. Endomixis ensued 

 on 4/4 in line Xb seven generations after its start, and in line Xa on 

 4/5 11 nine generations after its start ; while in line X the next endomixis 

 occurred on 4/10, 12 eighteen generations after Xa and b were branched 

 off from it. It is interesting to note that both lines Xa and b died, 

 Xa immediately and Xb very shortly, upon transfer to pure distilled 

 water on 4/11. While the division rate was notably reduced prior to 

 their death, they were nevertheless able to survive great dilution of the 

 culture medium with H 2 0, but were not able to bear transfer from the 

 greatly diluted medium to pure H 2 itself. 



Experiment 11 (fig. XI) 



In this experiment line XI was branched off from line IV on 5/22 

 in a 1:1 mixture of beef extract solution and distilled water and car- 

 ried gradually into pure distilled water on 6/3 with daily changes of 

 slide. Endomixis occurred on 6/1 seventeen generations after the 

 line was started, whereas in the parent line IV it did not occur until 

 6/9 thirty-eight generations after. 



In the following experiments temperature was the experi- 

 mental agent, the experimental lines being suddenly transferred 



11 Since there was no division of line Xa on 4/5 it is impossible to say whether 

 endomixis occurred then or not until 4/6 when the first record of it was obtained. 

 The cessation of division of 4/5, and the nuclear conditions on 4/6 are strong 

 presumptive evidence of its occurrence on 4/5. The point is immaterial in any 

 event. 



12 My record regarding this endomixis is uncertain. In all probability one 

 occurred at this time. But if it did not occur, then the influence of the distilled 

 water in inducing endomixis in lines X a and b becomes more pronounced than 

 if it did. 



