196 DROSKRA ROTUNDIPOLIA. [Chap. X. 



yet in contact with some phosphate previously placed on two 

 glands in the centre of the disc, the exterior tentacles on the 

 same side were acted on. 



When a gland is first excited, the motor impulse is dis- 

 charged within a few seconds, as we know from the bending 

 of the tentacle; and it appears to be discharged at first with 

 much greater force than afterwards. Thus, in the case 

 above given of a small fly naturally caught by a few glands 

 on one side of a leaf,, an impulse was slowly transmitted from 

 them across the whole breadth of the leaf, causing the op- 

 posite tentacles to be temporarily inflected, but the glands 

 which remained in contact with the insect, though they con- 

 tinued for several days to send an impulse down their own 

 pedicels to the bending place, did not prevent the tentacles 

 on the opposite side from quickly re-expanding; so that the 

 motor discharge must at first have been more powerful than 

 afterwards. 



When an object of any kind is placed on the disc, and the 

 surrounding tentacles are inflected, their glands secrete more 

 copiously and the secretion remains acid, so that some in- 

 fluence is sent to them from the discal glands. This change 

 in the nature and amount of the secretion cannot depend on 

 the bending of the tentacles, as the glands of the short cen- 

 tral tentacles secrete acid when an object is placed on them, 

 though they do not themselves bend. Therefore I inferred 

 that the glands of the disc sent some influence up the sur- 

 rounding tentacles to their glands, and that these reflected 

 back a motor impulse to their basal parts; but this view 

 was soon proved erroneous. It was found by many trials 

 that tentacles with their glands closely cut off by sharp scis- 

 sors often become inflected and again re-expand, still ap- 

 pearing healthy. One which was observed continued healthy 

 for ten days after the operation. I therefore cut the glands 

 off twenty-five tentacles, at different times and on different 

 leaves, and seventeen of these soon became inflected, and 

 afterwards re-expanded. The re-expansion commenced in 

 about 8 hrs. or 9 hrs., and was completed in from 22 hrs. 

 to 30 hrs. from the time of inflection. After an interval of 

 a day or two, raw meat with saliva was placed on the discs 

 of those seventeen leaves, and when observed next day, seven 

 of the headless tentacles were inflected over the meat as close- 



