350 GLANDULAR HAIRS, Crap. XV. 
employed. A solution of this strength paralyses al] movement 
in Drosera, but does not kill the protoplasm; a still stronger 
solution prevents the protoplasm from aggregating into the 
ordinary full-sized globular masses, and these, though they 
do not disintegrate, become granular and opaque. In nearly 
the same manner, too hot water and certain solutions (for 
instance, of the salts of soda and potash) cause at first an 
imperfect kind of aggregation in the cells of Drosera; the little 
masses afterwards breaking up into granular or pulpy brown 
maiter. All the foregoing experiments were made on flower- 
stems, but a piece of a leaf was immersed for 30 m. in a strong 
solution of the carbonate (one part to 109 of water), and little 
globular masses of matter appeared in all the glands, which 
before contained only limpid fluid. 
I made also several experiments on the action of the vapour 
of the carbonate on the glands; but will give only a few cases. 
The cut end of the footstalk of a young leaf was protested with 
sealing-wax, and was then placed wi der a small bell-glass, with 
a large pinch of the carbonate. After 10 m. the glands showed 
a considerable degree of aggregation, and the protoplasm lining 
the cells of the pedicels was a little separated from the walls. 
Another leaf was left for 50 m. with the same result, excepting 
that the hairs became throughout their whole length of a 
brownish colour. Ina third leaf, which was exposed for 1 hr. 
50 m., there was much aggregated matter in the glands; and 
some of the masses showed signs of breaking up into brown 
granular matter. This leaf was again placed in the vapour, 
so that it was exposed altogether for 5 hrs. 30 m.; and now, 
though I examined a large number of glands, aggregated 
masses were found in only two or three; in all the others, 
the masses, which before had been globular, were converted 
into brown, opaque, granular matter. We thus see that 
exposure to the vapour for a considerable time produces the same 
effects as long immersion in a strong solution. In both cases 
there could hardly be a doubt that the salt had been absorbed 
chiefly or exclusively by the glands. 
On another occasion bits of damp fibrin, drops of a weak in- 
fusion of raw meat and of water, were left for 24 hrs. on some 
leaves; the hairs were then examined, but to my surprise differed 
in no respect from others which had not been touched by these 
fluids. Most of the cells, however, included hyaline, motionless 
little spheres, which did not seem to consist of protoplasm, 
but, I suppose, of some balsam or essential oil. 
Pelargonium zonale (var. edged with white).—The leaves 
