180 DROSERA ROTUNDIFOLIA. [CniP. IX. 



i'ury which the leaves had suffered, whether any anesthetic effect 

 lad been produced. 



A third plant, having two good leaves, was exposed for only 4 

 ni. in the Jl)-oz. vessel to the vapour from six drops. Bits of meat 

 were then phiced on the glands of seven tentacles on the same leaf. 

 A single tentacle moved after 1 hr. 23 m. ; after 2 hrs. 3 m. several 

 were inflected; and after 3 hrs. 3 m. all the seven tentacles with 

 meat were well inflected. From the slowness of these movements 

 it is clear that this leaf had been rendered insensible for a time 

 to the action of the meat. A second leaf was rather difTerently 

 affected; bits of meat were placed on the glands of five tentacles, 

 three of which were slightly inflected in 28 m.; after 1 hr. 21 m. 

 one reached the centre, but the other two were still only slightly 

 inflected; after 3 hrs. they were much more inflected; but even 

 after 5 hrs. 16 m. all five had not reached the centre. Although 

 some of the tentacles began to move moderately soon, they after- 

 wards moved with extreme slowness. By next morning, after 20 

 hrs., most of the tentacles on both leaves were closely inflected, 

 but not quite regularly. After 48 hrs. neither leaf appeared in- 

 jured, though the tentacles were still inflected; after 72 hrs. one 

 was almost dead, whilst the other was re-expanding and recov- 

 ering. 



Carbonic Acid. A plant was placed under a 122 -oz. bell-glass 

 filled with this gas and standing over water; but I did not make 

 Buflicient allowance for the absorption of the gas by the water, so 

 that towards the latter part of the experiment some air was 

 drawn in. After an exposure of 2 hrs. the plant was removed, and 

 bits of raw meat placed on the glands of three leaves. One of 

 these leaves hung a little down, and was at first partly and soon 

 afterwards completely covered by the water, which rose within 

 the vessel as the gas was absorbed. On this latter leaf the ten- 

 tacles, to which meat had been given, became well inflected in 2 m. 

 30 s., that is, at about the normal rate; so that until I remem- 

 bered that the leaf had been protected from the gas, and might 

 perhaps have absorbed oxygen from the water which was con- 

 tinually drawn inwards, I falsely concluded that the carbonic acid 

 had produced no effect. On the other two leaves, the tentacles 

 with meat behaved very differently from those on the first leaf; 

 two of them first began to move slightly in 1 hr. 50 m., always 

 reckoning from the time when the meat was placeil on the glands - 

 were plainly inflected in 2 hrs. 22 m. and in 3 hrs. 22 m. reached 

 the centre. Three other tentacles did not begin to move until 2 

 hrs. 20 m. had elapsed, but reached the centre at about the same 

 time with the others, viz. in 3 hrs. 22 m. 



This experiment was repeated several times with nearly the 

 same results, excepting that the inter^'al before the tentacles began 

 to move varied a little. I will give only one other case. A plant 

 was exposed in the same vessel to the gas for 4.5 m., and bits of 

 meat were then placed on four glands. But the tentacles did not 

 move for 1 hr. 40 ni.; after 2 hrs. 30 m. all four were well inflected, 

 and after 3 hrs. reached the centre. 



