Car. VIL PHOSPHATE OF AMMONIA. 157 
flected ; and one was not at all acted on. By an accident only 
fifteen, instead of eighteen, leaves were immersed at the same 
time in water; these were observed for 24 hrs.; one had six, 
another four, and a third two, of their outer tentacles inflected ; 
the remainder being quite unaffected. 
The next experiment was tried under very favourable circum- 
stances, fort he day (July 8) was very warm, and I happened 
to have unusually fine leaves. Five were immersed as before in 
a solution of one part to 131,250 of water (1 gr. to 300 oz.), sc 
that each received z)55 of a grain, or 0135 mg. After an 
immersion of 25 m. all five leaves were much inflected. After 
1 hr. 25 m. one leaf had all but eight tentacles inflected; the 
second, all but three; the third, all but five ; the fourth, all but 
twenty-three; the fifth, on the other hand, never had more 
than twenty-four inflected. Of the corresponding five leaves in 
water, one had seven, a second two, a third ten, a fourth one, 
and a fifth none inflected. Let it be observed what a contrast 
is presented between these latter leaves and those in the solu- 
tion. I counted the glands on the second leaf in the solution, 
and the number was 217; assuming that the three tentacles 
which did not become inflected absorbed nothing, we find 
that each of the 214 remaining glands could have absorbed 
only yostc00 Of a grain, or ‘0000631 mg. The third leaf bore 
236 glands, and subtracting the five which did not become in- 
flected, each of the remaining 231 glands could have absorbed 
only ryohsc0 Of a grain (or ‘0000584 mg.), and this amount 
sufficed to cause the tentacles to bend. 
Twelve leaves were tried as before in a solution of one part to 
175,000 of water (1 gr. to 400 0z.), so that each leaf received ¢255 
of a grain (0101 mg.). My plants were not at the time in 
a good state, and many of the leaves were young and pale. 
Nevertheless, two of them had all their tentacles, except three 
or four, closely inflected in under 1 hr, Seven were con- 
siderably affected, some within 1 hr., and others not until 3 hrs., 
4 hrs. 30 m., and 8 hrs. had elapsed; and this slow action 
may be attributed to the leaves being young and pale. Of 
these nine leaves, four had their blades well inflected, and a 
fifth slightly so. The three remaining leaves were not affected. 
With respect to the twelve corresponding leaves in water, not 
one had its blade inflected; after from 1 to 2 hrs. one had 
thirteen of its outer tentacles inflected; a second six, and four 
others either one or two inflected. After 8 hrs. the outer 
tentacles did not become more inflected; whereas this occurred 
with the leaves in the solution. I record in my notes that 
