EFFECT OF CONJUGATION 



305 



a coefficient of variation of 30.828 ± 3.890. For the 18 non- 

 conjugant lines the mean is 13.500 ± 0.425; the standard devi- 

 ation 2.G72 ± 0.300, the coefficient of variation 19.792 ± 2.310. 

 Thus here, as in all other cases, the rate of fission is a Httle 

 greater in the non-conjiigants, while the variability is much 

 greater in the progeny of the conjugants than in that of the non- 

 conjugants. 



TABLE 10 



Experiment 4. Paramecium aurelia. Number of fissions for the conjugants and 

 non-conjuganls during the twenty days of experiment 4 {October 19 to Nove^nher 

 8, 1908). 



Where the mortality is so high as in this case, it is doubtless 

 due mainly to extrinsic causes, so that its distribution is of little 

 significance. The facts are these: of 42 lines descended from 

 conjugants, 25 died out during the twenty days of the experiment, 

 a mortality of 59.52 per cent. Of the 38 lines descended from 

 non-conjugants, 20 died out, a mortality of 52.63 per cent. Thus 

 the mortality is, as usual, greatest among the descendents of 

 the conjugants. 



Experiments 5 to IJj^: Comparatwe effects of repeated conjugation, 

 and of long abstention from conjugation 



During the year 1910 a \'ery extensive series of experiments 

 was carried on with the pure race k, for testing the relative effects 

 of conjugation and of abstention from conjugation. The whole 

 series was so bound together that it might well be considered one 

 prolonged experiment; it will be convenient, however, in giving 

 an account of it, to designate as separate experiments the various 

 phases of it. 



