INHERITANCE IN ABNORMALITIES 397 



large individuals, never dividing, do not appear after conjuga- 

 tion in all cultures; some later attempts to obtain them for 

 study have not been successful. 



IV. TYPES OF ABNORMAL RACES 



Of chief interest for our purposes are the exconjugants which 

 divided, but produced progeny some of which were deformed. 

 The lines of descent to which these deformed individuals belong 

 I shall call abnormal lines or races; it is they that provide the 

 material for the study of heredity, variation, and selection here 

 set forth. 



The abnormal lines differ greatly in the proportion of abnormal 

 individuals produced and in their later history. Not all the 

 individuals produced are abnormal; and not all the abnormal 

 races remain abnormal indefinitely. Reserving many of the 

 details for our section on the results of selection, we may divide 

 these abnormal races into three classes: 



1. In the first class are those races which ultimately became 

 normal. There were 39 races of this class. The proportion of 

 abnormal individuals produced ranges in the different races from 

 one per cent to 41 per cent. In these races the abnormal indi- 

 viduals gradually disappear, till finally only normals are pro- 

 duced. Some of the abnormals of this class may be compared 

 with the experimentally deformed animals ; and with those which 

 arise rarely in cultures that have not conjugated. They always 

 form a very small proportion of their race, and either die out 

 or produce normal daughter cells. Others however are not 

 strictly comparable with the transient abnormalities described 

 by other workers. They form a considerable and constant pro- 

 portion of the individuals of their race ; are continually produced 

 for several generations; and are often descended from both nor- 

 mal and abnormal sister cells. But through the action of natu- 

 ral conditions and in some cases the selection of the normal indi- 

 viduals, the abnormals become gradually eliminated and the 

 race entirely normal. Data on these 39 races of the three 

 experiments is given in table 2. 



