19 MISS A. BATESON AND MR. £. DARWIN ON THE EFFECT OF 
Exp. 9.—July 29, 1886. Dandelion; screw method. 
Times of observation. Rate *. 
A.M. 
11.389  ...............- 76 (in water). 
16 
85 
11425 .................. 66 
Transferred to a jar of 
3 per cent. alcohol. 
71 
47 
26 
1145 . .................. Alcohol added (6 per cent. 
mixture). 
35 
1465 An. 36 
. Experiment 9 and other similar trials showed that a fresh 
acceleration of growth can be produced by repeated doses of 
alcohol. The effect of immersing the pith in pure methylated 
spirit surprised us much ; and is the only result which caused us 
to doubt whether the aleohol may not act in some inexplicable 
mechanical way, and not as a stimulus. Pure methylated spirit 
causes’ an extremely rapid * growth," lasting for a few minutes, 
followed, as might. be expeeted, by death and contraction. The 
only analogous case which.we know of is when a split flower- 
stalk is put in hot water. The stalk continues to curl up violently 
owing to inereased turgescence, and then, as the tissue gets 
heated throughout, it dies and uncurls. It is not easy to see how 
the aleohol ean stimulate without killing the tissues; and we 
should have expected that it would have caused contraction, as 
in the ease of other poisons. Although this point is a difficulty, 
we do not think it fatal to our conclusion that turgescent pith is 
stimulated to inereased growth by alcohol. 
2. Stimulating Effect of Ether Vapour. 
The effects of ether and chloroform on plants is the subject of 
an extremely interesting papert by Dr. Elfving of Helsingfors. 
He has shown that ether and chloroform have a stimulating 
effect on respiration, and a highly remarkable action on the sen- 
sibility to light of swarm-spores. He has alse tested the effects 
of the above vapours on the rate of growth of Phycomyces; and 
“* That is, rate of movement of the index. 
t Ofversigt af Finska Vetensk.-Soc. Förh. Bd. xxviii. - 
