INHERITANCE IN ABNORMALITIES 407 



V. NATURE OF THE ABNORMALITIES 



Descriptively considered, the abnormalities shown by the indi- 

 viduals of the abnormal races are of many diverse sorts. I have 

 been able to distinguish 40 different types of abnormals. These 

 are shown in figure 9, and their frequenf;ies in the three experi- 

 ments are given in table 4. Most of the races of Experiment 1 

 developed one or more representatives of a large number of 

 these types; some of the races had representatives of all but 

 two or three. The high frequencies of so many of these types 

 in Experiment 1 , as given in table 4 shows how great the diver- 

 sity of form is among the individuals of that group. In experi- 

 mentally produced abnormalities reported by other workers on 

 other animals, this diversity of type is always shown; as Mall 

 ('08) says, there is never found any precise type of abnormality 

 characteristic of certain conditions, but only a general character, 

 a tendency to abnormality of many different types. But some 

 races of my experiments were more or less characterized by a 

 few types, which I have called their predominant types. The 

 best examples of this predominance of type are race C of Experi- 

 ment 1, and races 56a, 56b, and 59b of Experiment 3. During 

 the early part of their histories these races showed considerable 

 diversity of abnormal type; but this diversity was rapidly re- 

 duced and the abnormals became limited to a few types in all 

 four of these races. During its whole history race C produced 

 in its observed cultures 2683 abnormals; 1331 or 50 per cent 

 of these were of type 33; 945 or 35 per cent were of type 27. 

 The predominant type of the other three races was the same, 

 number 27 of figure 9. Race 56a produced 1428 abnormals; 

 79 per cent of them were of that type; 59 per cent of the 780 

 abnormals of 56b were of type 27; and 50 per cent of the 2096 

 abnormals of race 59b were of the same type. 



In the abnormals of Experiment 2 there was considerably less 

 diversity of type than in the abnormals of Experiment 1 . Only 

 30 of the different types were observed in Experiment 2; most of 

 these appeared only a small number of times, 90 per cent of the 

 abnormals being of five types (11, 26, 27, 28, 30). Table 4 gives 



