72 DROSERA ROTUNDIFOLIA. Chap. rV> 



Experiment 11. — A leaf was imrDersed in water at 145° (62° '7 

 Cent.), which was raised to 156° (68° '8 Cent.). The tentacles 

 became bright red and somewhat reflexed, with almost all the 

 glands like porcelain; those on the disc being still pinkish, 

 those near the margin quite white. The leaf being placed as 

 usnal first in cold water and then in the strong solution, the 

 cells in the tentacles became of a muddy greenish brown, with 

 the protoplasm not aggregated. Nevertheless, four of the glands 

 escaped being rendered like porcelain, and the pedicels of these 

 glands were spirally curled, like a French horn, towards their 

 upper ends; but this can by no means be considered as a 

 case of true inflection. The protoplasm within the cells of the 

 twisted portions was aggregated into distinct though excessively 

 minute purple spheres. This case shows clearly that the proto- 

 plasm, after having been exposed to a high temperature for a 

 few minutes, is capable of aggregation when afterwards sub- 

 jected to the action of carbonate of ammonia, unless the heat 

 has been suflGicient to cause coagulation. 



Concluding RemarJcs. — As the hair-like tentacles are 

 extremely thin and have delicate walls, and as the 

 leaves were waved about for some minutes close to the 

 bulb of the thermometer, it seems scarcely possible 

 that they should not have been raised very nearly to 

 the temperature which the instrument indicated. 

 From the eleven last observations we see that a tem- 

 perature of 130*^ (54°-4 Cent.) never causes the imme- 

 diate inflection of the tentacles, though a temperature 

 from 120" to 125° (48°-8 to 51°-6 Cent.) quickly pro- 

 duces this effect. But the leaves are paralysed only 

 for a time by a temperature of 130°, as afterwards, 

 whether left in simple water or in a solution of car- 

 bonate of ammonia, they become inflected and their 

 protoplasm undergoes aggregation. This great dif- 

 ference in the efiects of a higher and lower tempera- 

 ture may be compared with that from immersion in 

 strong and weak solutions of the salts of ammonia ; for 

 the former do not excite movement, whereas the latter 

 act energetically. A temporary suspension of the 



