210 



HEREDITY AND SEX 



history of six such ex-conjugants is shown in the next 

 diagram (Fig. 101). The four lines, "quadrants," 

 (1, 2, 3, 4) that are descended from each of six ex- 

 conjugants (viz. G, H, L, M, Q, B) are shown. At 

 intervals large numbers of the populations were put 

 under conditions favorable to conjugation and the 



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Fig. 101. — History of six (G, H, L, M, Q, B) ex-conjugants. In each 

 the descendants of the first four individuals (after conjugation) is shown; 

 the numbers indicate the pairs of conjugants counted when the test was 

 made. X indicates deaths; O indicates that no conjugation took place. 

 (After Calkins.) 



number of conjugating pairs counted. The results 

 are shown in the diagram. The circles indicate no 

 conjugations ; X indicates the death of the strain. 

 In the G and in the M series many conjugations took 

 place. In other series conjugation did not take place 

 until much later. Striking differences appear in the 

 different quadrants although they were kept under 

 similar conditions. 



