hrs. had all its tentacles except eight inflected, were counted and
found to be 202. Subtracting the eight, each gland could have received
only the 1/1552000 grain (.0000411 mg.) of the phosphate. Leaf No. 9
had 213 tentacles, all of which, with the exception of four, were
inflected after 24 hrs., but none of them closely; the blade was also
inflected; each gland could have received only the 1/1672000 of a
grain, or .0000387 mg. Lastly, leaf No. 11, which had after 24 hrs. all
its tentacles, except one, closely inflected, as well as the blade,
bore the unusually large number of 252 tentacles; and on the same
principle as before, each gland could have absorbed only the 1/2008000
of a grain, or .0000322 mg.
With respect to the following experiments, I must premise that the
leaves, both those placed in the solutions and in water, were taken
from plants which had been kept in a very warm greenhouse during the
winter. They were thus rendered extremely sensitive, as was shown by
water exciting them much more than in the previous experiments. Before
giving my observations, it may be well to remind the reader that,
judging from thirty-one fine leaves, the average number of tentacles is
192, and that the outer or exterior ones, the movements of which are
alone significant, are to the short ones on the disc in the proportion
of about sixteen to nine. [page 161]
Four leaves were immersed as before, each in thirty minims of a
solution of one part to 328,125 of water (1 gr. to 750 oz.). Each leaf
thus received 1/12000 of a grain (.0054 mg.) of the salt; and all four
were greatly inflected.
(1) After 1 hr. all the outer tentacles but one inflected, and the
blade greatly so; after 7 hrs. began to re-expand.
(2) After 1 hr. all the outer tentacles but eight inflected; after 12
hrs. all re-expanded.
(3) After 1 hr. much inflection; after 2 hrs. 30 m. all the tentacles
but thirty-six inflected; after 6 hrs. all but twenty-two inflected;
after 12 hrs. partly re-expanded.
(4) After 1 hr. all the tentacles but thirty-two inflected; after 2
hrs. 30 m. all but twenty-one inflected; after 6 hrs. almost
142