1905] MCCALLUM—REGENERATION IN PLANTS 103 
opment of one terminal bud.” Many tuber- and bulb-forming 
plants do not normally produce seeds, but, as in Lilium candidum, 
Lachenalia luteola, etc., if the bulbs be cut away and prevented from 
forming, seeds will be produced. “In the normal condition,” Gor- 
BEL says, “seed formation is hindered because the plastic material 
which might be used for seeds streams 
into the bulb.” The inference is that 
this material, prevented from going to 
the bulbs, will flow to the seeds. This. 
conception plays a fundamental part in 
GOEBEL’s explanation of how the 
removal of one part may start the 
development of another. Sacus (10) 
gives a similar explanation for the 
development of the cotyledonary buds 
in Phaseolus, stating that it is due to 
increase of food resulting from the 
removal of the main axis. To demon- 
strate this it must be shown that these 
lateral buds, though in intimate con- 
tact with large cotyledons, remain. 
undeveloped because of lack of food, 
and further that when the terminal bud 
is removed they will not develop if the 
possibility of an increased amount of 
food is precluded. 
The attempt is made in the follow- 
ing experiments to determine this experimentally. The plants used, 
unless otherwise stated, were seedlings, the epicotyl varying from 1 
tog*™ long, with the first pair of leaves not yet fully opened, and 
the cotyledons still full of food (fig. 4). 
If an increase of nutritive material in the axial primordia, due to 
the removal of the parts using this while the source of supply is still 
active, is the cause of development of these structures, then while 
removing the central shoot, if we at the same time remove the source 
of the food, there should be no development of the primordia. 
Experiment 1.—Twelve plants were used, the epicotyl was cut 
“Fic. 4 
. 
