344 
GENETICS: T. H. GOODSPEED 
Following the castration or mutilation of these 800 buds, there were 
112 bags, involving nearly 200 flowers, in which one or more fruits 
developed to normal size. These fruits contained matured seed all of 
which was normal in appearance, though the majority was small in size, 
and a small proportion of which was normal in every way including the 
presence of endosperm and embryos. That there is a ready and frequent 
parthenocarpy, taking this term simply to indicate the production of 
normal fruits without pollination, in 'Nic. tahaccum Cuba' there can be 
no doubt. This is the more remarkable since other Nicotiana species 
and varieties uniformly exhibit an early dropping of those flowers in 
which emasculation is not closely followed by pollination. It may be 
noted that, of the castrations and mutilations which were followed by 
the production of normal fruits, 75% were on the terminal inflorescence 
and the four or five 'bald suckers,' normal to this variety of N. Tabacum, 
and 25% only were on the lower leafy laterals. Similarly, buds treated 
within two weeks after the opening of the first flower on the plant ma- 
tured fruits in 65 instances as compared with 57 instances in the case of 
treatments performed after that period. Certain plants were not treated 
until they had passed their first and heaviest flowering period. Such 
plants gave no significant increase in the proportion of fruits matured 
after treatment. The number of fruits matured from treated buds 
under 35 mm. in length was almost identical with the number produced 
from treated buds more than 35 mm. long. Almost equal numbers of 
four-parted and five-parted flowers produced fruits following treatment. 
However, seed containing endosperm and embryos or endosperm only 
seems to have resulted, in nearly all cases, from the treatment of the 
more normally formed, five-parted flowers. Similarly, the use of a 
single bud on an inflorescence for treatment seems, as was perhaps to be 
expected, to have been more efficient for the production of normal seed 
than the castration of more than one. Of the total SOO treatments less 
than one-third involved the pinching off of the stigma in addition to 
emasculation. Approximately one-tenth of the total number involved 
the pinching off of the stigma only. Nine treated flowers produced a 
little viable seed and, of these nine flowers, three represent treatments 
in which the stigma was removed. 
The great majority of the seed produced in the parthenocarpic fruits 
was normal in appearance and well filled out but these seeds were 
smaller than the self-pollinated seeds and consisted of empty seed coats 
only. Samples of seed from each seed packet were bleached in strong 
Eau de Javelle and examined under magnification. Controls were em- 
