No. 591] TBANSMISSION OF DEGENERACY 



151 



litters of one than from the litters of two. Not one de- 

 formed animal has resulted from these normal inbred 

 matings and only one individual of the thirty was less 

 than two thirds the average weight. The few normal in- 

 bred young here considered are then equally as good as 

 the young from normal non-relatives and necessarily su- 

 perior to the alcoholic lines. Judging from the results of 

 others, there is little doubt that a more extensive inbreed- 

 ing might produce deleterious effects. 



The last vertical column indicates the effects of in- 

 breeding alcoholic animals and their descendants. This 

 combination shows the- poorest quality offspring found in 

 the table. Here again the members of the larger litters 

 are at a disadvantage when compared with those born in 

 the small litters. The average number of young in a 

 litter is 1.62, somewhat smaller than the litters produced 

 by mating alcoholic non-relatives. Thirty-eight litters 

 contained a single individual each, the same number of 

 litters contained two individuals, while only seven litters 

 consisted of three young, and these were the largest litters 

 produced. The inbred alcoholic animals, therefore, have 

 a tendency to produce a large proportion of small litters 

 and this tendency aids in strengthening their offspring. 



Of the 135 young resulting from these matings, only 

 36.29 per cent, of them survived; this is the poorest life 

 record shown by any combination. Of those born only 

 one in a litter, however, 76.31 per cent, survived, which is 

 a record equal to the average of the control. Therefore, 

 even in this very bad combination, alcoholic inbreeding, 

 when only one young is produced at a litter by an animal 

 ordinarily capable of producing two or more, this one 

 young is so well nourished and accommodated that it is 

 somatically vigorous. Yet on breeding such individuals 

 it almost always happens that very inferior offspring re- 

 sult. The germ cells, at any rate, may possibly be 

 stronger than those in the weaker individuals which oc- 

 curred in litters of two or three. Only 26.31 per cent, of 

 the animals born in litters of two were capable of sur- 



