276 DEOSERA ROTUNDIFOLIA. Chap. XI. 



inflected ; though the inflection may last for many 

 days. 



If the bending place of a tentacle receives an impulse 

 from its own gland, the movement is always towards 

 the centre of the leaf; and so it is with all the 

 tentacles, when their glands are excited by immer- 

 sion in a proper fluid. The short ones in the middle 

 part of the disc must be excepted, as these do not 

 bend at all when thus excited. On the other hand, 

 when the motor impulse comes from one side of the 

 disc, the surrounding tentacles, including the short 

 ones in the middle of the disc, all bend with pre- 

 cision towards the point of excitement, wherever this 

 may be seated. This is in every way a remarkable 

 phenomenon ; for the leaf falsely appears as if en- 

 dowed with the senses of an animal. It is all the 

 more remarkable, as when the motor impulse strikes 

 the base of a tentacle obliquely with respect to its 

 flattened surface, the contraction of the cells must be 

 confined to one, two, or a very few rows at one end. 

 And diff'erent sides of the surrounding tentacles must 

 be acted on, in order that all should bend with pre- 

 cision to the point of excitement. 



The motor impulse, as it spreads from one or more 

 glands across the disc, enters the bases of the sur- 

 rounding tentacles, and immediately acts on the bend- 

 ing place. It does not in the first place proceed up 

 the tentacles to the glands, exciting them to reflect 

 back an impulse to their bases. Nevertheless, some 

 influence is sent up to the glands, as their secre- 

 tion is soon increased and rendered acid; and then 

 the glands, being thus excited, send back some other 

 influence (not dependent on increased secretion, nor 

 on the inflection of the tentacles), causing the proto- 

 plasm to aggregate in cell beneath cell. This may 



