CHAP. I. ACTION OF THE PAKTS. 11 



solution is at all strong, the leaf is paralysed), all the 

 exterior tentacles bend inwards (see fig. 4), excepting 

 those near the centre, which remain upright ; but these 

 bend towards any exciting object placed on one side 

 of the disc, as shown in fig. 5. The glands in fig. 4 

 may be seen to form a dark ring round the centre ; and 

 this follows from the exterior tentacles increasing in 

 length in due proportion, as they stand nearer to the 

 circumference. 



The kind of inflection which the tentacles undergo 

 is best shown when the gland of one of the long exterior 



FIG. 6. 



(Drosera rotundifolia.) 



Diagram showing one of the exterior tentacles closely inflected ; the two adjoining 

 ones in their ordinary position. 



tentacles is in any way excited ; for the surrounding 

 ones remain unaffected. In the accompanying outline 

 (fig. 6) we see one tentacle, on which a particle of 

 meat had been placed, thus bent towards the centre of 

 the leaf, with two others retaining their original 

 position. A gland may be excited by being simply 

 touched three or four times, or by prolonged contact 

 with organic or inorganic objects, and various fluids. I 

 have distinctly seen, through a lens, a tentacle begin- 

 ning to bend in ten seconds, after an object had been 



