MODIFICATION OF THE GERM-CELLS IN MAMMALS 183 



10. TREATING MALES WITH ALCOHOL FOR ONE AND TWO GENERA- 

 TIONS AGAINST TREATING FEMALES FOR ONE AND 

 TWO GENERATIONS 



An experiment has now been in progress for some time in 

 which straight male lines have been treated with alcohol for sev- 

 eral generations in order to compare the results with those from 

 the treatntent of straight female Hnes for several generations. 

 That is, the original males are treated, their sons are then di- 

 rectetly treated, their grandsons, great-grandsons, and so on; 

 these we consider the straight male lines. The treated females, 

 their directly treated daughters, granddaughters, and so on 

 constitute the straight female lines. There are now a few third- 

 and fourth-generation individuals, though not a sufficient num- 

 ber to tabulate. We shall thus for the present confine our 

 attention to the records from the originally selected and treated 

 males and females and the treated sons of these males and 

 daughters of the females. 



The records are arranged in table 5. In considering the 

 table it must be stated that the original animals in this experi- 

 ment have been carefully selected large strong specimens that 

 were particularly good breeders. Such a choice has been made 

 on account of the severity of the treatment to which the de- 

 scendants are to be subjected through a number of generations. 

 Only the best animals are likely to produce descendants suffi- 

 ciently strong to be treated with alcohol and to continue to re- 

 produce for one generation after another. The fact that such 

 a selection is possible does not reflect on the general population, 

 since no population is so perfect that certain individuals are not 

 better than others. This selection probably accounts for the 

 presence in all the groups of table 5 of some offspring of unusually 

 large size. 



The pedigrees or conditions of the animals in the different 

 generations are expressed by the following symbols or formulae. 

 A normal animal is represented by the letter N and one treated 

 with alcohol by A. The symbol for the male is placed to the 

 right of that for the female. Thus the first column NN are the 

 normal control animals for comparison, the second column NA 



