Cuap. VIL PHOSPHATE OF AMMONIA. 153 
88 m.; a third, eighteen inflected, after 1 hr.; and a fourth, 
ten inflected, after 35 m. The four other leaves were not in 
the least affected. Of the eight corresponding leaves in water, 
one had, after 2 hrs. 10 m., nine tentacles, and four others from 
one to four long-headed tentacles, inflected; the remaining three 
being unaffected. Hence, the gy, of a grain given to a sensi- 
tive leaf during warm weather perhaps produces a slight effect ; 
but we must bear in mind that occasionally water causes as 
great an amount of inflection as occurred in this last ex- 
periment. 
Summary of the Results with Nitrate of Ammonia. 
The glands of the disc, when excited by a half-minim 
drop (0296 ml.), containing <4, of a grain of the 
nitrate (027 mg.), transmit a motor impulse to the 
exterior tentacles, causing them to bend inwards. A 
minute drop, containing 7,1, of a grain (00225 mg.), 
if held for a few seconds in contact with a gland, 
causes the tentacle bearing this gland to be inflected 
If a leaf is left immersed for a few hours, and some- 
times for only a few minutes, in a solution of such 
strength that each gland can absorb only the ssps55 
of a grain (0000937 mg.), this small amount is 
enough to excite each tentacle into movement, and 
it becomes closely inflected. 
PHOSPHATE OF AMMONIA. 
This salt is more powerful than the nitrate, even 
in a greater degree than the nitrate is more powerful 
than the carbonate. This is shown by weaker solu- 
tions of the phosphate acting when dropped on the 
discs, or applied to the glands of the exterior ten- 
tacles, or when leaves are immersed. The difference 
in the power of these three salts, as tried in three 
different ways, supports the results presently to be 
