1905] McCCALLUM—REGENERATION IN PLANTS 109 
cylinder, so that the lower part of the stem of each plant passed 
through a rubber stopper inserted in the bottom of the cylinder. 
Thus the stem and foliage were in the cylinder, the cotyledons were 
below in the air, and the roots hung down into a nutrient salt solu- 
tion. The cylinder was lined with wet filter paper and covered at the 
top. The plants grew rapidly, but the basal primordia did not develop. 
Experiment 14.—Three other plants were arranged in the same 
way, except that the cylinders were filled with water instead of moist 
air. The stems grew rapidly for a few days, then the growth gradually 
decreased, and finally ceased entirely. No development of the basal 
buds occurred until growth ceased, when they developed. This was 
repeated by inverting three plants with their foliage in a large aqua- 
rium, with the same result. When the shoots were killed by the pro- . 
longed submergence, however, the basal buds developed shoots. 
Experiment 15.—All the foliage was cut from five plants, thus 
removing the transpiration surface, and no development of basal buds 
followed. All the leaves and also the cotyledons were removed from 
three other plants, with the same result. 
Experiment 16.—Five large plants, with six to eight internodes 
and a large display of foliage were selected. The vegetative tip was 
removed from each and also the buds in the axils of all the leaves. 
In four of them the basal buds developed. Here the disturbance in 
the water content could only have been trifling, for careful deter- 
mination before and after cutting off the tips showed no appreciable 
diminution in the amount of transpiration. . 
Experiment 17.—A second moist chamber that kept the plant 
saturated was formed in the following way: a glass tube was drawn 
to a fine end with a capillary opening and through this a fine jet of 
Water was forced, which struck a small piece of ground glass held 
obliquely to it and was scattered into a fine mist. In this mist five 
plants were set, the fine spray continuously settling on every part of 
the plant, not only. the upper but also the under surface, for it cir- 
culated freely on the slight air currents always present. Here the 
plants were covered constantly with a thin layer of water, which com- 
pletely checked transpiration, but the excellent aeration allowed a 
healthy growth. All the plants grew rapidly, but there was no 
development of the buds at the base. 
