CHANGES IN CELL-ORGANS OF DROSERA ROTUNDIFOLIA. 3893 
EXPERIMENTS. 
With the view of observing the minute histological changes 
induced by functional activity in the gland-cells of Drosera 
rotundifolia experiments were made as follows. 
I. In Perthshire, Scotland, in the beginning of September, 
1895, leaves were fed with the white of a soft-boiled egg, cut 
into pieces approximately 5 mm. in length by 1 mm. in breadth 
and thickness. The leaves were fixed after the following 
intervals of time :—one hour, twenty-four hours, forty-eight 
hours, seventy-two hours. These intervals were chosen in 
order that the leaves might be fixed at the same time of day 
in each case to avoid all variations due to diurnal changes. 
Young vigorous leaves, which showed no trace of having had 
a previous meal, were likewise fixed at the same times, and the 
whole experiment was conducted while the plants were growing 
in their native habitat, an open moor. 
II. Another series of experiments was made in May, 1896, 
in Berkshire, England, where the leaves were again fed without 
being removed from their natural habitat, and fixed at intervals 
of from one minute up to the time when the leaves had again 
fully expanded and appeared to have regained their normal 
condition, which varied with the vigour of the leaf from four 
to seven days. 
III. Repetition of experiment in August, 1896, in Scotland, 
to determine changes induced by an insoluble tissue, namely, 
boiled pieces of cork. 
IV. A number of plants were removed for convenience to a 
cool greenhouse, and their leaves were fixed at various intervals 
after feeding. 
In each set of experiments 15—20 leaves were used for 
each period of time, e. g. twenty leaves to determine changes 
after one minute, twenty leaves to show alterations after two 
minutes, &c. 
The results of the four sets of experiments coincided on the 
