203 DROSERA ROTUNDIPOLIA. [Chap. X 



a continuous zigzag line of vessels round the whole circum- 

 ference. But the union of the vessels in this zigzag line 

 seems to be much less intimate than at the main inoscula- 

 tion. It should be added that the course of the vessels dif- 

 fers somewhat in different leaves, and even on opposite sides 

 of the same leaf, but the main inosculation is always present. 



Now in my first experiments with bits of meat placed on 

 one side of the disc, it so happened that not a single tentacle 

 was inflected on the opposite side ; and when I saw that the 

 vessels on the same side were all connected together by the 

 two inosculations, whilst not a vessel passed over to the op- 

 posite side, it seemed probable that the motor impulse was 

 conducted exclusively along them. 



In order to test this view, I divided transversely with the 

 point of a lancet the central trunks of four leaves, just be- 

 neath the main bifurcation ; and two days afterwards placed 

 rather large bits of raw meat (a most powerful stimulant) 

 near the centre of the discs above the incision that is, a 

 little towards the apex with the following results: 



(1) This leaf proved rather torpid: after 4 hrs. 40 m. (in all 

 cases reckoning from the time when the meat was given) the ten- 

 tacles at the distal end were a little inflected, but nowhere else; 

 they remained so for three days, and re-expanded on the fourth 

 day. The leaf was then dissected, and the trunk, as well as the 

 two sublateral branches, were found divided. 



(2) After 4 hre. 30 m. many of the tentacles at the distal end 

 were well inflected. Next day the blade and all the tentacles at 

 this end were strongly inflected, and were separated by a distinct 

 transverse line from the basal half of the leaf, which was not in 

 the least afTected. On the third day, however, some of the short 

 tentacles on the disc near the base were very slightly inflected. 

 The incision was found on dissection to extend across the leaf as 

 in the last case. 



(3) After 4 hrs. 30 m. strong inflection of the tentacles at the 

 distal end, which during the next two days never extended in the 

 least to the basal end. The incision as before. 



(4) This leaf was not observed until 1.5 hrs. had elapsed, and 

 then all the tentacles, except the extreme marginal ones, were 

 found equally well inflected all round the leaf. On careful ex- 

 amination the spiral vessels of the central trunk were certainly 

 divided; but the incision on one side had not passed through the 

 fibrous tissue surrounding these vessels, though it had passed 

 through the tissue on the other side.* 



M. Zlegler made similar ox- (' Comptes rondtis.* 1874, p. 1417), 

 perlmonts hy cnttlnjt the spiral Imt nrrlvcnl at conrluslooa widely 

 vessels of Droacra intermedia clillcreDt from nilne. 



