172 DROSERA ROTUNDIFOLIA. (Cuar. IX. 
were next brushed only once with the same brush and in the same 
manner us before; the results are given in the table. My first trials 
were made by brushing the leaves whilst still immersed in the 
solution; but it occurred to me that the viscid secretion round the 
glands would thus be removed, and the camphor might act more 
effectually on them. In all the above trials, therefore, each leaf 
was taken out of the solution, waved for about 15 s. in water, then 
placed in fresh water and brushed, so that the brushing would not 
allow the freer access of the camphor; but this treatment made no 
difference in the results. 
Other leaves were left in the solution without being brushed; one 
of these first showed a trace of inflection after 11 m.; a second after 
12 m.; five were not inflected until 15 m. had elapsed, and two not 
until a few minutes later. On the other hand, it will be seen in the 
right-hand column of the table that most of the leaves subjected to the 
solution, and which were brushed, became inflected in a much shorter 
time. The movement of the tentacles of some of these leaves was so 
rapid that it could be plainly seen through a very weak lens. 
Two or three other experiments are worth giving. A large old leaf, 
after being immersed for 10 m. in the solution, did not appear likely 
to be soon inflected; so I brushed it, and in 2 m. it began to move, 
and in 8 m. was completely shut. Another leaf, after an immersion 
of 15 m., showed no signs of inflection, so was brushed, and in 4m. 
was grandly inflected. A third leaf, after an immersion of 17 m., 
likewise showed no signs of inflection ; it was then brushed, but did 
not move for 1 hr.; so that here was a failure. It was again brushed, 
and now in 9 m. a few tentacles became inflected; the failure therefore 
was not complete. 
We may conclude that a small dose of camphor in solution is a 
powerful stimulant to Drosera. It not only scon excites the tentacles 
to bend, but apparently renders the glands sensitive to a touch, which 
by itself does not cause any movement. Or it may be that a slight 
mechanical irritation not enough to cause any inflection yet gives some 
tendency to movement, and thus reinforces the action of the camphor. 
This latter view would have appeared to me the more probable one, 
had it not been shown by M. Vogel that camphor is a stimulant in 
other ways to various plants and seeds. 
Two plants bearing four or five leaves, and with their roots ina 
little cup of water, were exposed to the vapour of some bits of camphor 
(about as large as w filbert nut), under a vessel holding ten fluid 
ounces. After 10 hrs. no inflection ensued; but the glands appeared 
to be secreting more copiously. ‘lhe leaves were in a narcotised con- 
dition, for on bits of meat being placed on two of them, there was no 
inflection in 3 hrs. 15 m., and even after 13 hrs, 15 m. only a few of 
the vuter tentacles were slightly inflected; but this degree of move- 
ment shows that the leaves had not been killed by an exposure during 
10 hrs. to the vapour of camphor. 
Oil of Caraway.—Water is said to dissolve about a thousandth 
