116 DROSERA ROTUNDIFOLIA. [Cuap. VII. 
other plants were placed with their roots surrounded by 
damp moss, in half an ounce (14:198 c.c.) of a solution of one 
part of the carbonate to 218 of water, and were observed for 
24 hrs.; but not a single tentacle was inflected. In order to 
produce this effect, the carbonate must be absorbed by the 
glands. 
The vapour produces a powerful effect on the glands, and 
induces inflection. Three plants with their roots in bottles, 
so that the surrounding air could not have become very 
humid, were placed under a bell-glass (holding 122 fluid 
ounces), together with 4 grains of carbonate of ammonia in a 
watch-glass. After an interval of 6 hrs. 15 m. the leaves 
appeared unaffected ; but next morning, after 20 hrs., the 
blackened glands were secreting copiously, and most of the 
tentacles were strongly inflected. These plants soon died. 
Two other plants were placed under the same _ bell-glass 
together with half a grain of the carbonate, the air being 
rendered as damp as possible; and in 2 hrs. most of the 
leaves were affected, many of the glands being blackened 
and the tentacles inflected. But it isa curious fact that some 
of the closely adjoining tentacles on the same leaf, both on the 
disc and round the margins, were much, and some, apparently, 
not in the least affected. The plants were kept under the 
bell-glass for 24 hrs., but no further change ensued. One 
healthy leaf was hardly at all affected, though other leaves on 
the same plant were much affected. On some leaves all the 
tentacles on one side, but not those on the opposite side, 
were inflected. I doubt whether this extremely unequal 
action can be explained by supposing that the more active. 
glands absorb all the vapour as quickly as it is generated, 
so that none is left for the others; for we shall meet with 
analogous cases with air thoroughly permeated with the 
vapours of chloroform and ether. 
Minute particles of the carbonate were added to the secre- 
tion surrounding several glands. These instantly became 
black and secreted copiously; but, except in two instances, 
when extremely minute particles were given, there was no 
inflection. This result is analogous to that which follows 
from the immersion of leaves in a strong solution of one part 
of the carbonate to 109, or 146, or even 218 of water, for the 
leaves are then paralysed and no inflection ensues, though 
the glands are blackened, and the protoplasm in the cells of 
the tentacles undergoes strong aggregation, 
