150 DROSERA ROTUNDIFOLIA. Cuap. VIL 
Having made some preliminary trials as a guide, five leaves 
were placed in the same little vessel in thirty minims of a sclu- 
tion of one part of the nitrate to 7875 of water (1 gr. to 18 02.); 
and this amount of fluid just sufficed to cover them. After 
2 hrs. 10 m. three of the leaves were considerably inflected, and . 
the other two moderately. The glands of all became of so dark 
a red as almost to deserve to be called’ black. After 8 hrs. four 
of the leaves had all their tentacles more or less inflected ; whilst 
the fifth, which I then perceived to be an old leaf, had only thirty 
tentacles inflected. Next morning, after 23 hrs. 40 m., all the 
leaves were in the same state, excepting that the old leaf had a 
few more tentacles inflected. Five leaves which had been placed 
at the same time in water were observed at the same intervals 
of time; after 2 hrs. 10 m. two of them had four, one had seven, 
one had ten, of the long-headed marginal tentacles, and the 
fifth had four round-headed tentacles, inflected. After 8 hrs. 
there was no change in these leaves, and after 24 hrs. all the 
marginal tentacles had re-expanded ; but in one leaf, a dozen, and 
in a second leaf, half a dozen, submarginal tentacles had become 
inflected. As the glands of the five leaves in the solution were 
simultaneously darkened, no doubt they had all absorbed a nearly 
equal amount of the salt: and as 53, of a grain was given to the 
five leaves together, each got z,, of a grain (045 mg.). I did 
not count the tentacles on these leaves, which were moderately 
fine ones, but as the average number on thirty-one leaves was 
192, it would be safe to assume that each bore on an average at 
least 160. If so, each of the darkened glands could have 
received only s3geqq Of a grain of the nitrate; and this caused 
the inflection of a great majority of the tentacles. 
This plan of immersing several leaves in the same vessel 
is a bad one, as-it is impossible to feel sure that the more 
vigorous leaves do not rob the weaker ones of their share of 
the salt. The glands, moreover, must often touch one another 
or the sides of the vessel, and movement may have been thus 
excited; but the corresponding leaves in water, which were 
little inflected, though rather more so than commonly occurs, 
were exposed in an almost equal degree to these same sources 
oferror, I will, therefore, give only one other experiment mado 
in this manner, though many were tried and all confirmed 
the foregoing and following results. Four leaves were placed 
in forty minims of a solution of one part to 10,500 of water; 
. and assuming that they absorbed equally, each leaf received 
xtsz of a grain (0562 mg... After 1 br. 20 m. many of the 
tentacles on all four leaves were somewhat inflected. After 
