INHERITANCE IN ABNORMALITIES 



435 



TABLE U 



Data from the nine lines of Race B in which the selection of abnormals tvas 



continuous 



hereditary differences in degree of abnormality. One set of lines 

 showed a very low degree, three lines becoming entirely normal. 

 The other set showed a very high degree of abnormality, one 

 line having 90 per cent of abnormals. 



We have then in race B the inheritance of a variation within 

 the clone; and a splitting up of the clone, both with and without 

 selection, into hereditarily diverse groups. 



The six races of Experiment 3 underwent a most strict selec- 

 tion of normals throughout their history; and in every case this 

 eventually brought about a change in the inheritance of the 

 abnormality. In each race all of the individuals arising from 

 the exconjugant were kept for the first six days; thereafter the 

 abnormals were discarded and only normals kept, as far as 

 possible. Abnormals were kept only when no normals were 

 present with which to carry on the race. In all these six ^-aces 

 this procedure had much the same effect. Some of their lines 

 were not .changed at all ; they continued to produce abnorn/als 

 from the normal cells selected. But other lines became entirely 

 normal. In every case there was inheritance of the variations 

 which had arisen within the clone. Figures 17, 18, 19, and 20 

 give pedigrees of four of these races, 56a and b, and 59a and b. 

 All six races are very similar in their history. On January 17 

 none of the six had completed their first division ; all had formed 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 19, NO. 4 



