Chap. XIII.] SECRETION AND ABSORPTION. 241 



We have seen that inorganic and non-nitrogenous objects 

 placed on the leaves do not excite any movement ; but nitrog- 

 enous bodies, if in the least degree damp, cause after several 

 hours the lobes to close slowly. Thus bits of quite dry meat 

 and gelatine were placed at opposite ends of the same leaf," 

 and in the course of 24 hrs. excited neither secretion nor 

 movement. They were then dipped in water, their surfaces 

 dried on blotting-paper, and replaced on the same leaf, the 

 plant being now covered with a bell-glass. After 24 hrs. the 

 damp meat had excited some acid secretion, and the lobes 

 at this end of the leaf were almost shut. At the other end, 

 where the damp gelatine lay, the leaf was still quite open, 

 nor had any secretion been excited ; so that, as with Drosera, 

 gelatine is not nearly so exciting a substance as meat. The 

 secretion beneath the meat was tested by pushing a strip of 

 litmus paper under it (the filaments not being touched), 

 and this slight stimulus caused the leaf to shut. On the 

 eleventh day it reopened ; but the end where the gelatine lay, 

 expanded several hours before the opposite end with the meat. 



A second bit of roast meat, which appeared dry, though it 

 had not been purposely dried, was left for 24 hrs. on a leaf, 

 caused neither movement nor secretion. The plant in its 

 pot was now covered with a bell-glass, and the meat absorbed 

 some moisture from the air; this sufficed to excite acid se- 

 cretion, and by the next morning the leaf was closely shut. 

 A third bit of meat, dried so as to be quite brittle, was 

 placed on a leaf under a bell-glass, and this also became in 

 24 hrs. slightly damp, and excited some acid secretion, but 

 no movement. 



A rather large bit of perfectly dry albumen was left at 

 one end of a leaf for 24 hrs. without any effect. It was then 

 soaked for a few minutes in water, rolled about on blotting- 

 paper, and replaced on the leaf; in 9 hrs. some slightly acid 

 secretion was excited, and in 24 hrs. this end of the leaf was 

 partially closed. The bit of albumen, which was now sur- 

 rounded by much secretion, was gently removed, and al- 

 though no filament was touched, the lobes closed. In this 

 and the previous case, it appears that the absorption of 

 animal matter by the glands renders the surface of the leaf 

 much more sensitive to a touch than it is in its ordinary 

 state; and this is a curious fact. Two days afterwards the 



