193 DROSERA ROTUNDIFOLIA. [Chap. X. 



tentacle being aflFceted. Other leaves were similarly pre- 

 pared, and bits of meat were placed on the glands of two 

 tentacles in the third row from the outside, and on the 

 glands of two tentacles in the fifth row. In these four cases 

 the impulse was sent in the first place laterally, that is, in 

 the same concentric row of tentacles, and then towards the 

 centre; but not centrifugally, or towards the exterior ten- 

 tacles. In one of these cases only a single tentacle on each 

 side of the one with meat was affected. In the three other 

 cases, from half a dozen to a dozen tentacles, both laterally 

 and towards the centre, were well inflected, or sub-inflected. 

 Lastly, in ten other experiments, minute bits of meat were 

 placed on a single gland or on two glands in the centre of 

 the disc. In order that no other glands should touch the 

 meat, through the inflection of the closely adjoining short 

 tentacles, about half a dozen glands had been previously re- 

 moved round the selected ones. On eight of these leaves 

 from sixteen to twenty-five of the short surrounding ten- 

 tacles were inflected in the course of one or two days ; so that 

 the motor impulse radiating from one or two of the discal 

 glands is able to produce this much effect. The tentacles 

 which had been removed are included in the above numbers; 

 for, from standing so close, they would certainly have been 

 aflFected. On the two remaining leaves, almost all the short 

 tentacles on the disc were inflected. With a more powerful 

 stimulus than meat, namely a little phosphate of lime moist- 

 ened with saliva, I have seen the inflection spread still far- 

 ther from a single gland thus treated; but even in this case 

 the three or four outer rows of tentacles were not affected. 

 From these exiwjriraents it appears that the impulse from a 

 single gland on the disc acts on a greater number of tentacles 

 than that from a gland of one of the exterior elongated ten- 

 tacles; and this probably follows, at least in part, from the 

 impulse having to travel a very short distance down the pedi- 

 cels of the central tentacles, so that it is able to spread to a 

 considerable distance all round. 



Whilst examining these leaves, I was struck with the fact 

 that in six, perhaps seven, of them the tentacles were much 

 more inflected at the distal and proximal ends of the leaf 

 (t. e. towards the apex and base) than on either side; and yet 

 the tentacles on the sides stood as near to the gland where 



