Cua. VIL. CARBONATE OF AMMONIA. 145 
tentacles become inflected within the same time, we have 
evidence, as before remarked, of simultaneous absorption. I 
did not count the number of glands on these four leaves; but 
as they were fine ones, and as we know that the average number 
of glands on thirty-one leaves was 192, we may safely assume 
that each bore on an average at least 170; and if so, each 
blackened gland could have absorbed only 57355 of a grain 
(00119 mg.) of the carbonate. 
A large number of trials had been previously made with 
solutions of one part of the nitrate and phosphate of ammonia to 
43750 of water (ie. one grain to 100 ounces), and these were 
found highly efficient. Fourteen leaves were therefore placed, 
each in thirty minims of a solution of one part of the carbonate 
to the above quantity of water; so that each leaf received zAy5 
of a grain ('0405 mg.). The glands were not much darkened. 
Ten of the leaves were not affected, or only very slightly so. 
Four, however, were strongly affected; the first having all the 
tentacles, except forty, inflected in 47 m.; in 6 hrs. 30 m. all 
except eight; and after 4 hrs. the blade itself. The second leaf 
after 9 m. had all its tentacles except nine inflected; after 6 hrs. 
30 m. these nine were sub-inflected; the blade having become 
much inflected in 4 hrs. The third leaf after 1 hr. 6 m. had all 
but forty tentacles inflected. The fourth, after 2 hrs. 5 m., had 
about half its tentacles and after 4 hrs. all but forty-five in- 
flected. Leaves which were immersed in water at the same time 
were not at all affected, with the exception of one; and this not 
until 8 hrs. had elapsed. Hence there can be no doubt that a 
highly sensitive leaf, if immersed in a solution, so that all the 
glands are enabled to absorb, is acted on by 75, of a grain of 
the carbonate. Assuming that the leaf, which was a large one, 
and which had all its tentacles excepting eight inflected, bore 
170 glands, each gland could have absorbed only sg¢gq5 of a 
grain ("00024 mg.); yet this sufficed to act on each of the 162 
tentacles which were inflected. But as only four out of the above 
fourteen leaves were plainly affected, this is nearly the mini- 
mum dose which is efficient. 
Aggregation of the Protoplasm from the Action of Curbonate of 
Ammonia.—I have fully described in the third chapter the 
remarkable effects of moderately strong doses of this salt in 
causing the aggregation of the protoplasm within the cells of 
the glands and tentacles; and here my object is merely to show 
what small doses suffice. A leaf was immersed in twenty 
tainims (1:183 ml.) of a solution of one part to 1750 of water, 
