44 DROSERA ROTUNDIFOLIA. Cuar. IIT. 
darken in 10 s. (seconds); and in 18 s. were conspicuously 
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 transverse 
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 
ageregated. 
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. Ifa few drops of a solution of one part of 
the carbonate to 487 of water (or 1 gr. to 1 0z.) be added to the 
purple fluid which exudes from crushed tentacles, or to paper 
stained by being rubbed with them, the fiuid 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 oz.); 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 Garbonate, for otherwise the colour would have 
been discharged. I have, however, sometimes observed, espe- 
cially 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, 
