VOLUME LI NUMBER 4 
IE 
BOTANICAL (ZAZETTE 
. | APRIL sr911 
ALTERATIONS IN HEREDITY INDUCED BY OVARIAL 
TREATMENTS 
D. Te MAacDoOUGAL 
(WITH PLATES XIV-XVI AND THREE FIGURES) 
During the course of an extended series of experimental cul- 
tures of the mutants of the oenotheras and of a.large number of 
other evening primroses native to America, the author conceived 
the idea early in 1905 that agencies of any kind which might affect 
the processes of the protoplasts concerned directly in the develop- 
ment of the embryo sac and the differentiation of the egg, and 
which inhibited or altered the reaction velocities of any process, 
whether catalytic or otherwise, might cause some alteration in the 
characters transmitted to the progeny arising from fertilizations 
into which had entered elements affected in this way. 
Brief announcements of the progress of the investigation have 
been made from time to time, as indicated by the appended bibli- 
ography, but it has been deemed advisable to present a résumé of 
the entire subject, which should include a description of the tech- 
nique and character of the plants employed, together with the 
results of the culture of the affected species through a number of 
Senerations. It may as well be stated in advance that the earlier 
conclusions, that the sum of hereditary characters in pedigreed 
ines of plants may be altered by solutions applied to the ovaries 
In the stage immediately preceding fertilization, are confirmed by 
the extended work on the matter, and that one of the earliest 
derivatives secured in this manner has been carried to the fifth 
a without showing indications of returning to the parental 
ype. 
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