GENETICS: R. PEARL 
677 
those obtained in the 1915 experiments, and even more pronounced 
in degree. 
c. The prenatal mortality is approximately 10%, and the postnatal 
mortality (to 180 days of age) is approximately 5% lower in the chicks 
with alcoholic ancestry than in those of non-alcoholic ancestry. 
d. While from a given number of eggs 26.78% fewer zygotes are 
formed in the alcoholic series than in the non-alcoholic, 10.7% more 
of those zygotes are alive when adult age (180 days) is reached if their 
ancestry was alcoholic than if it was non-alcoholic. 
e. The great reduction in zygote formation (partial sterility) ob- 
served in the alcohol treated series is preponderantly due to the effect 
of the alcohol . upon the germ cells of the female. While there is some 
diminution in the effective fecundity of the male as a result of the treat- 
ment, it is much smaller than in the female. In the first two lines of 
the table, where the dam is alcoholic, we have 22 and 8% of the eggs 
forming embryos, as against values of from 54 to 68% where the sire 
is alcoholic and the dam not. The lower value for the percentage of 
zygote formation in the case of matings where the dam only is alcoholic 
as compared with those in which both parents are alcoholic, almost 
certainly does not represent a significant difference, but is an accidental 
result of the small number of matings in the class. The significant 
thing is the fact that the percentage of zygote formation steadily rises 
as we compare the following groups: (1) dam alone or dam and sire 
alcoholic, (2) sire alone or sire and some other ancestry not including 
the dam alcoholic, (3) no ancestry alcoholic. 
3. In the season of 1916 every fertile egg in which the embryo died 
on or after the tenth day of incubation was opened, and an examination 
was made of the embryo in each case, in order to determine whether 
any structural abnormality or malformation was present. It was not 
found practicable to deal with embryos under ten days of age. A detailed 
record was kept of all such congenital abnormalities, in both the dead 
embryos and hatched chicks. Every discernible departure from per- 
fect structural normahty was taken account of, the range including 
at one extreme such slight and unimportant things as the congenital 
absence of one toenail in an otherwise perfectly normal chick, and at 
the other extreme acraniate and eyeless monsters. A later complete 
report will give the detailed data for the different classes of abnor- 
malities. Here I wish simply to report the general results. These 
are set forth in Table 2. 
