142 DEOSEKA EOTUNDIFOLIA. Chap. VII. 



did not bend. Two other plants were placed with 

 their roots surrounded by damp moss, in half an ounce 

 (14*198 ml.) of a solution of one part of the carbo- 

 nate to 218 of water, and were observed for 24 hrs. ; 

 but not a single tentacle was inflected. In order to 

 produce this effect, the carbonate must be absorbed 

 by the glands. 



The vapour produces a powerful effect on the glands, 

 and induces inflection. Three plants with their roots 

 in bottles, so that the surrounding air could not have 

 become very humid, were placed under a bell-glass 

 (holding 122 fluid ounces), together with 4 grains 

 of carbonate of ammonia in a watch-glass. After an 

 interval of 6 hrs. 15 m. the leaves appeared unaffected ; 

 but next morning, after 20 hrs., the blackened glands 

 were secreting copiously, and most of the tentacles 

 were strongly inflected. These plants soon died. 

 Two other plants were placed under the same bell- 

 glass, together with half a grain of the carbonate, the 

 air being rendered as damp as possible ; and in 2 hrs. 

 most of the leaves were affected, many of the glands 

 being blackened and the tentacles inflected. But it is 

 a curious fact that some of the closely adjoining ten- 

 tacles on the same leaf, both on the disc and round 

 the margins, were much, and some, a]3parently, not in 

 the least affected. The plants were kept under the 

 bell-glass for 24 hrs., but no further change ensued. 

 One healthy leaf was hardly at all affected, though 

 other leaves on the same plant were much affected. 

 On some leaves all the tentacles on one side, but not 

 those on the opposite side, were inflected. I doubt 

 whether this extremely unequal action can be ex- 

 plained by supposing that the more active glands 

 absorb all the vapour as quickly as it is generated, so 

 that none is left for the others for we shall meet with 



