STIMULATION ON TURGESCENT VEGETABLE TISSUES. 13 
it is this point which especially interests us. He found that 
1 per cent. of ether had no effect, 2 per cent. a distinctly retarding 
effect, while 5 per cent. brought growth toa standstill, but without 
killing the hyphe. 
It will be seen that our results are not necessarily opposed to 
Elfving’s. In the first place, he experimented on a different 
plant; and, secondly, he does not give any results with per- 
centages lower than 1 per cent. Whereas in our case the stimu- 
lating effect of ether was greatest when the vapour was present 
in strengths below 1 per cent. 
In our experiments the pith was allowed to “ grow” in damp air ; 
in some cases it was previously wetted; but usually pith was em- 
ployed which had not been so treated. A known quantity of 
ether was then poured into the jar of known capacity. The 
mouth of the cylinder was closed by a divided glass disk which 
allowed the passage of the thread attaching the pith to the lever. 
The atmosphere of ether was thus kept as constant in strength as 
was possible. 
There can be no doubt that the vapour of ether has a marked 
accelerating effect. 
The following Table shows the percentage of ether in the 
atmospheres which caused acceleration, the amount of quickening 
being given in a parallel column :— 
Percentage Acceleration of 
ofether. growth. 
Men 100 : 118 
1020) BE 100 : 156 
037 Lees 100 : 146 
040 ............. eee 100 : 200 
In raising the strength ofthe ether by successive additions, 
acceleration of growth was observed on each addition; but no 
acceleration was observable when the strength had been raised to 
about 1:2 per cent.* 
* In one case a very slight acceleration occurred when the strength was 
suddenly raised from 1:80 per cent. to 4'5 per cent.; and this was quickly 
followed by contraction and death. 
