MODIFICATION OF THE GERM-CELLS IN MAMMALS 163 



The distribution of the animals in large and small litters is 

 closely the same as in the two preceding columns, over 30 per 

 cent being in litters of less than three and 20.09 per cent in litters 

 larger than three. The average-size litter and the average litter 

 weight are just about what is found for the total alcoholic group 

 and somewhat better than for the Fi group. The percentage 

 of surviving animals is a little better than the total alcoholic 

 group and considerably better than the Fi group. The prenatal 

 and postnatal mortality proportions follow the typical arrange- 

 ment for the alcoholic lines, the prenatal being about two and 

 one-third times higher than the postnatal. The total mortality 

 among these anAials is about 10 per cent lower than for the Fi 

 group and slightly below the record of the total alcoholic lines. 

 When the mortality is corrected in terms of the normal mortality 

 for the different-size litters and stated on the basis of 100 for the 

 control stock, it becomes 172 as against 230, for the Fi column 

 and 189 for the all generations alcoholic column. 



The fifth column records 147 animals still further removed 

 from the treated generation; these had treated great-grandpar- 

 ents or great-great-grandparents or both, the F3 and F4 genera- 

 tions. Some of these animals may have had only one or two 

 alcoholic ancestors out of eight or sixteen; therefore, the pro- 

 portion of modified to normal germ plasm is often very small. 



The arrangement in large and small litters differs from the 

 other alcoholic groups and approaches that shown by the nor- 

 mal lines very closely, there being a higher percentage born in 

 large litters than in small. The average-size litter is larger 

 than in the three preceding columns, although still well below 

 the control. The average litter weight is low when compared 

 with the normal lines and only about the same as in the three 

 preceding columns when taken in connection with the average 

 size of the litters. When corrected for the average size, the 

 weight of the litter falls more than 10 grams below the control 

 record. The mating failures still show the high percentage of 

 the alcoholic lines, being over three times as many as in the 

 control. 



