Mar., 1923] ROSA — EFFECT OF BORDEAUX MIXTURE II5 
of the plant as a whole. When rain comes, growth again proceeds vigor¬ 
ously for a few days. The tuber development resulting from such spurts 
of growth, in the case of the Early Ohio variety, seems to consist very 
largely in knobby protuberances from the eyes, especially at the tips of 
Fig. 2. Knotty protuberances or second growths on tubers of early Ohio potatoes 
from plots sprayed four times with Bordeaux mixture. 
tubers previously formed. As many as four or five distinct growth zones 
could be identified on some of the knotty tubers from the sprayed plots. 
It is hoped that further experiments can be carried out to learn the limits 
of variation in soil moisture which the potato will endure without devel¬ 
oping second growths, as well as the relation of certain other edaphic factors 
to tuberization. The state of dormancy in tubers whose growth is checked 
as above indicated is also a question of some interest, for if removed from 
the plant these tubers would not commence stem growth for many weeks. 
Another interesting question suggested by the observations described 
above is the value of tubers bearing second growths for seed purposes. 
If variation in soil moisture or in some other environmental factor causes 
tubers to develop second growth in Missouri, this defect may arise from 
the same causes in Wisconsin, Minnesota, or other seed-growing section. 
Then tubers bearing second growth would not necessarily be weak or de- 
