168 DROSERA ROTUNDIFOLIA. Cuar. VIL 
salts of ammonia which were tried, all cause the in- 
flection of the tentacles, and often of the blade of 
the leaf. As far as can be ascertained from the 
superficial trials with the last six salts, the citrate is 
the least powerful, and the phosphate certainly by far 
the most. The tartrate and chloride are remarkable 
from the short duration of their action. The rela- 
tive efficiency of the carbonate, nitrate, and phos- 
phate, is shown in the following table by the smallest 
amount which suffices to cause the inflection of the 
tentacles. 
Solutions, how applied. Carbonate of pelldilas of Phosphate of 
‘ F z ‘ 
Placed on the glands of 
the disc, so as to act ato, OF @ ning of & mary Of & 
indirectly on the outer (| 27?» OF | gral, or grain, or 
fantacles\ +: ; -0675 mg. “027 mg. “0169 mg. 
Applied for a few se-); 
conds directly to thel| Ls Pa — rate is : 
4 2 
gland of an outer!'.90445 mg.| +0025 mg. | 000428 mg. 
Leaf immersed, with 1 of 1 of F ¢ 
time allowed for each repemp OF @) = — aptapy OF & roTeoqo0 OF a 
gland to absorb all{’, 8™% oF grain, or grain, or 
Hint ik ean _ 3") 00024 mg.| +0000937 mg. | -00000328 mg. 
Amount absorbed by a 
gland which suffices 
to cause the aggre-|| qstgy of @ 
gation of the proto-) grain, or 
plasm in the adjoin-| -00048 mg. 
ing cells of the ten- -| 
tacles . 
From the experiments tried in these three dif- 
ferent ways, we see that the carbonate, which con- 
tains 23'7 per cent. of nitrogen, is less efficient than 
the nitrate, which contains 35 per cent. The phos. 
phate contains less nitrogen than either of these 
salts, namely, only 212 per cent., and yet is far more 
