168 



DROSEKA ROTUNDIFOLIA. 



CUAP. VII. 



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, bow applied. 



Carbonate of 

 I Ammonia. 



Nitrate of 

 Ammonia. 



Phosphate of 

 Ammonia. 



Placed on the glauds of j 

 the disc, so as to act [ 

 iudii-ectly on the outer j 

 tentacles ... J 



Applied for a few se-] 

 conds directly to the I 

 gland of an outer | 

 tentacle . . . .j 



Leaf immersed, with]! ^ 



time allowed for each ' ' ^dss 

 gland to absorb all 

 that it can 



Amount absorbed by a 

 gland which suffices 

 to cause the aggre- 

 gation of the proto- 

 plasm in the adjoin- 

 ing cells of the ten- 

 tacles 



965 of a 

 grain, or 

 •0675 mg. 



nW of a 



grain, or 



■00445 mg. 



of a 

 gram, or 

 00024 mg. 



ishm of a 



grain, or 



■00048 mtr 



51155 of a 

 grain, or 

 •027 mg. 



553755 of a 



grain, or 

 •0025 m^. 



mhm of a 



grain, or 



•0000937 mj 



5515 of a 

 grain, or 

 •01G9 msc. 



133555 of a 



grain, or 

 •000423 mg. 



T97B5555 of a 



grain, or 

 •00000328 m< 



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 



