128 DROSERA ROTUNDIFOLIA. [Cuar. VII: 
the eighteen were only slightly affected, having twenty-one, nineteen, 
and twelve tentacles inflected; 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 circumstances, 
for the day (July 8) was very warm, and I happened to have 
unusually tine leaves, Five were immersed as before in a solution of 
one part to 131,250 of water (1 gr. to 300 oz.), so that each received 
adua fa grain, or *0135 mg. Afteranimmersion 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 solution. 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 giands could 
have absorbed only yga7uqo Of a grain, or *0000631 mg. The third 
leaf bore 236 glands, and subtracting the five which did not become 
inflected, each of the remaining 231 glands could have absorbed only 
sioisoo 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 535, of 2 
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 considerably 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. 
record in my notes that after the 8 hrs. it was impossible to compare 
the two lots, and doubt for an instant the power of the solution. 
Two of the above leaves in the solution had all their tentacles, 
except three and four, inflected within an hour. I counted their 
glands, and, on the same principle as before, each gland on one leaf 
could have absorbed only zzg¢so, and on the other leaf only 1474000 
of a grain of the phosphate. 
