On Evil in Small Doses 
A great many other cases might be quoted to show 
how general seems to be this law, viz. that something 
evil is an excellent stimulus if administered in small 
doses. But it will be better to show exactly what 
happens in crises of this kind, 
Certain gladiolus bulbs were carefully tested in order 
to find out the exact amount of carbonic acid given off 
in ordinary respiration. These bulbs were then treated 
with the utmost cruelty. Some were poisoned with ether, 
and were found to breathe five times as quickly as they did 
under normal conditions ; others were placed in a high 
temperature, and these also breathed at double the rate. 
Some were submerged in cold water for twenty-four 
hours, and others were bruised and injured in various 
ways, but in every case the result was a more rapid and 
intense respiration.™4 
When onion bulbs are cut or slashed, every wound 
increases the amount of carbonic acid given off in 
respiration. 
When potatoes are cut, or the seedlings of various 
vegetables are injured by removing the root-tip or slicing 
the cotyledons, the respiration increases in every case, 
and only becomes normal after the wound has been 
healed.*® 
But it has also been found that when plants are 
suffering from the attacks of fungi or of insect enemies, 
their respiration is more intense, Not only so, but when 
a rust-fungus has established itself upon a living plant, 
all the normal life-processes are intensified and accele- 
rated. More water is given off in transpiration, more 
sugar and other material is produced by assimilation, 
and the breathing is also more rapid and vigorous.1¢ 
We have already mentioned the efforts made by a 
leaf to cut out an injured spot by a sort of surgical 
operation performed of its own initiative. The growth 
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