518 



G. N. CALKINS AND L. H. GREGORY 



Calkins' paper of 1902 also deals with split conjugations, the 

 method employed being exactly the same as that adopted by 

 Jennings. The details of the experiments however, were not 

 given and are here published from the records of 1902 for the 

 first time. 



The conjugating pairs used in the splitting experiments were 

 obtained from mixtures of series A and series B. Series A at 

 this time were in the 376th generation and Series B in the 334th, 

 and the mixtures were made by putting together in Syracuse 

 dishes the stock left over from all lines of A and B after isolat- 

 ing the culture individuals. There is thus, no record of the exact 

 origin of the split conjugating pairs. Of the twelve individuals 

 whose history was followed after the operation of splitting two 

 died with in two days, three more died in four days, one in eight 

 days, one in eleven days, one in twenty-five days, one in thirty 



TABLE 8 



