38 DROSERA ROTUNDIFOLIA. (Cuar. III. 
darker. In 1m. extremely small spherical masses of protoplasm could 
be seen arising in the cells of the pedicels close beneath the glands, as 
well as in the cushions on which the long-headed marginal glands rest. 
In several cases the process travelled down the pedicels for a length 
twice or thrice as great as that of the glands, in about 10 m. It was 
interesting to observe the process momentarily arrested at each trans- 
verse partition between two cells, and then to see the transparent 
contents of the cell next below almost flashing into a cloudy mass. 
In the lower part of the pedicels, the action proceeded slower, so that it 
took about 20 m. before the cells halfway down the long marginal and 
submarginal tentacles became aggregated. 
We may infer that the carbonate of ammonia is absorbed by the 
glands, not only from its action being so rapid, but from its effect being 
somewhat different from that of other salts. As the glands, when 
excited, secrete an acid belonging to the acetic series, the carbonate is 
probably at once converted into a salt of this series; and we shall 
presently see that the acetate of ammonia causes aggregation almost 
or quite as energetically as does the carbonate. If a few drops of a 
solution of one part of the carbonate to 437 of water (or 1 gr. to 1 oz.) 
be added to the purple fluid which exudes from crushed tentacles, or 
to paper stained by being rubbed by them, the fluid and the paper are 
changed into a pale dirty green. Nevertheless, some purple colour 
could still be detected after 1 hr. 30 m. within the glands of a leaf left _ 
in a solution of twice the above strength (viz. 2 grs. to 1 0z.); and 
after 24 hrs. the cells of the pedicels close beneath the glands still 
contained spheres of protoplasm of a fine purple tint. These facts 
show that the ammonia had not entered as a carbonate, for otherwise 
the colour would have been discharged. I have, however, sometimes 
observed, especially with the long-headed tentacles on the margins of 
very pale leaves immersed in a solution, that the glands as well as the 
upper cells of the pedicels were discoloured; and in these cases I 
presume that the unchanged carbonate had been absorbed. The 
appearance above described, of the aggregating process being arrested 
for a short time at each transverse partition, impresses the mind with 
the idea of matter passing downwards from cell to cell. But as 
the cells one beneath the other undergo aggregation when inorganic 
and insoluble particles are placed on the glands, the process must be, at 
least in these cases, one of molecular change, transmitted from the 
glands, independently of the absorption of any matter. So it may 
possibly be in the case of the carbonate of ammonia. As, however, 
the aggregation caused by this salt travels down the tentacles at a 
quicker rate than when insoluble particles are placed on the glands, it 
is probable that ammonia in some form is absorbed not only by the 
glands, but passes down the tentacles. 
Having examined a leaf in water, and found the contents of the 
cells homogeneous, I placed it in a few drops of a solution of one part 
of the carbonate to 437 of water, and attended to the cells immediately 
beneath the glands, but did not use a very high power. No aggrega- 
