524 G. N. CALKINS AND L. H. GREGORY 



thermore, a ''split" conjugant separated from a pair just begin- 

 ning conjugation, from the same pure line, divided 180 times, the 

 control non-conjugant divided 181 times and the ex-conjugant 

 divided 211 times in one hundred and fifty days. 



10. We do no wish to take the stand that variations do not 

 follow from amphimixis. This fact is too well established in the 

 higher animals and plants to be denied in the case of Paramecium, 

 but it has not been proved for Paramecium. The only way it 

 can be proved is by a systematic study of variations in many 

 different pure lines from an ex-conjugant and comparing the re- 

 sults of such study with similar results derived from a like study 

 of different ex-conjugants. 



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