L68 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. Carhonate of ay itrate of puceDbate of 
Placed on the glands of 
the disc, so as to act aig. of el 0 ake sary of @ 
airs glam aa Dee Sor s r wie9" ‘3 
tentacles . mg: mg. me. 
Applied for a few se-), 
eonds directly to the|! ss ie ge ida of 
gland of an outer|’. 2 3 ’ : d 
tentacle _),00445 mg. 0025 mg. 000423 mg. 
Leaf immersed, with : 
time allowed for each lagi ve he indo ee 
gland to absorb all ’ : 2 
thatutwan ss ) *00024 mg.| 0000937 mg. | *00000228 mg. 
Amount absorbed by a 
gland which suffices | 
to cause the aggre-|' isfy of a 
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 21:2 per cent., and yet is far more 
