CHANGES IN CELL-ORGANS OF DROSERA ROTUNDIFOLIA. 391 
panying Stimulation in the Gland-cells of Drosera di- 
chotoma,” in which he described the phenomenon of aggre- 
gation in living stalk cells, much as Darwin had done. He 
also noticed the phenomenon produced by the action of car- 
bonate of ammonia, and called it “ passive aggregation.” A 
spindle-shaped or acicular body in the stalk cells and epidermal 
cells of the leaf called a “rhabdoid” is also described, which, 
as well as the elongated nuclei of the stalk cells, tends to be- 
come spherical after long stimulation. 
Gardiner studied also the changes in the appearance of the 
gland-cells themselves after stimulation. His methods were 
as follows : 
Leaves stimulated from five minutes to seventy-two hours 
by feeding with flies, or small pieces of frog’s muscle, were 
examined fresh, or after fixing in alcohol, picric acid, or osmic 
acid. The best results were got with specimens treated for 
twelve hours with 1 per cent. or 2 per cent. solution of chromic 
acid. He describes a typical resting gland-cell thus :—‘“ The 
protoplasm is arranged in a network or reticulum. The meshes 
of this reticulum are excessively close around the nucleus, 
which is situated at the base of the cell; but towards the free 
surface they are much more open, the close and more open 
arrangement merging the one into the other. The meshwork 
extends through the whole cell-cavity, and the interstices be- 
tween the meshes are occupied by a pink cell-sap, and the 
whole is bounded by a structureless ectoplasm. In neither of 
the three layers of cells covering the tracheidal cells of the 
head could any obvious movement of the protoplasm be de- 
tected.” 
After stimulation for twenty-four hours the following histo- 
logical changes were observed : 
“ A gland mounted in water exhibited a mottled appearance, 
such mottling being caused by a vacuolation of the most peri- 
pheral portions of the protoplasm of the gland-cells. In 
section, such a cell showed that in the course of secretion 
there had been a using up of the cell contents, and instead of 
the meshwork occupying the whole of the peripheral portion 
