50 DROSERA ROTUNDIPOLIA. [Chap. II L 



sigrns of a current could be seen within these ruptured cells. 

 They had evidently been killed by the pressure; and the 

 matter which they still contained did not undergo aggre- 

 gation any more than that which had exuded. In these 

 specimens, as I may add, the individuality of the life of each 

 cell was well illustrated. 



A full account may be given in the next chapter of the 

 effects of heat on the leaves, and I need here only state that 

 leaves immersed for a short time in water at a temperature 

 of 120 Fahr. (48.8 Cent.), which, as we have seen, does 

 not immediately induce aggregation, were then placed in a 

 few drops of a strong solution of one part of carbonate of 

 ammonia to 109 of water, and became finely aggregated. 

 On the other hand, leaves, after an immersion in water at 

 150** {Q5.5 Cent.), on being placed in the same strong 

 solution, did not undergo aggregation, the cells becoming 

 filled with brownish, pulpy, or muddy matter. With leaves 

 subjected to temperatures between these two extremes of 

 120 and 150 Fahr. (48.8 and 65.5 Cent.), there were 

 gradations in the completeness of the process; the former 

 temperature not preventing aggregation from the subse- 

 quent action of carbonate of ammonia, the latter quite stop- 

 ping it. Thus, leaves immersed in water, heated to 130** 

 54*'.4 Cent.), and then in the solution, formed perfectly 

 defined spheres, but these were decidedly smaller than in or- 

 dinary cases. With other leaves heated to 140** (60** Cent.), 

 the spheres were extremely small, yet well defined, but many 

 of the cells contained, in addition, some brownish pulpy 

 matter. In two cases of leaves heated to 145 (G2.7 Cent.), 

 a few tentacles could be found with some of their cells con- 

 taining a few minute spheres; whilst the other cells and 

 other whole tentacles included only the brownish, disinte- 

 grated or pulpy matter. 



The fluid within the cells of the tentacles must be in an 

 oxygenated condition, in order that the force or influence 

 which induces aggregation should be transmitted at the 

 proper rate from cell to cell. A plant, with its roots in 

 water, was left for 45 m. in a vessel containing 122 fluid oz. 

 of carbonic acid. A leaf from this plant, and, for com- 

 parison, one from a fresh plant, were both immersed for 1 hr. 

 in a rather strong solution of carbonate of ammonia. They 



