EFFECT OF CONJUGATION 



287 



very great, and will be well brought out by examining side by 

 side certain weekly records for the first fifteen individuals of 

 each set (table 1). 



TABLE 1 



Experiment 1. Pnrdnieciiini cdudatum. Number of fissions per iveek for the first 15 

 lines of each set (d = dead). 



First week. 



Pairs 



Split pairs. . 

 Second week: 



Pairs 



Split pairs. . , 

 Third week:. . . 



Pairs 



Split pairs. . 



3. All those which have not conjugated multiply, while among 

 those that have conjugated are a considerable number that either 

 never divide again, although they may live for a long time; or 

 divide but few times. This will be evident from examination of 

 the general record table (table 29, Appendix). 



4. A considerable number of the lines derived from those that 

 have conjugated die out, while none of the others die out (table 

 29). 



5. It is evident on a cursory examination of the records that 

 among the lines derived from the conjugants there is much 

 greater variation in the rate of fission than among those derived 

 from the indi\dduals that have not conjugated. 



Each of these points will now be taken up in detail and the 

 facts precisely brought out. 



The weekly records for the entire experiment are given in 

 table 29 (Appendix), which serves as a basis for the following 

 discussion. 



Fifth week not typical. One point should be brought out at 

 the beginning of the analysis. During the fifth week the lines 

 of propagation were in an unhealthy condition owing to extrane- 

 ous reasons. On May 31, at the end of the fourth week, the 

 experiment was tried of mixing a little starch from boiled bread 



