ON THE PHYSICAL POWER OF INSECTS. 
231 
he looks forward for his harvest crops, ruining his orchards, annoying his domestic 
animals, and in the warmer latitudes not even sparing himself. It may seem 
strange that such reasons should be brought forward to urge the necessity of our 
making ourselves acquainted with the works of insects, but I believe it is per¬ 
fectly legitimate to do so; for it is to be remembered, that here, as elsewhere, 
knowledge may be power, and that with the power derived from a ^knowledge of 
their economy we may frequently see these destroyers overcome. 
In primeval forests, and in countries where vegetation remains as yet unchecked 
by the hand of man, the labours of insects seem often as if appointed as a curb 
on luxuriant vegetation. In Europe, and in other parts of the world under his 
care, no such check is now needed; nevertheless they return as originally ap¬ 
pointed in the order of the universe. Their appearance is often at distant 
intervals, and quite inexplicable; every effort is made by the sufferers from their 
ravages to put a stop to their devastations ; and it is only by a careful attention 
to their economy that this can be attained. Knowing from example, as we now 
do, how to destroy a large proportion of the eggs of the Corn Weavel, that insect 
is no longer the dreadful scourge of the granary that it once was. 
In the vicinity of London, in St. James’s and the Green Park, a few year 8 
back, the trees were observed to be stripped of their bark ; at first some wanton 
mischievous persons were supposed to be the cause of the injury; the Ranger 
launched his edicts against them, and appointed a watch to lead to their detection > 
the evil increased—in vain did the anxious watchman try to bring to light the 
offenders ; it was not until an entomologist had explained the cause of the injury * 
and how to proceed to remove it, that the trees were restored to their wonted 
health. It is not always, however, that the labours of entomologists in this 
sphere have been so successful. 
A gentleman in Liverpool, well known for his zeal in this department of science, 
has informed me of two interesting cases that have recently occurred in France 
and Germany, where the utmost skill of the naturalists of both these countries 
has been baffled. The Vines of Burgundy had received much injury from the 
attacks of the larva of a small Moth. At the urgent request of the proprietors 
of the Vine-yards, the French government employed Professor Audouin, of the 
Jardin des Plantes,, to see if he could provide an antidote for the evil. After a 
thorough investigation of the Vines, he found that the only mode of removing the 
insects was by placing a number of lamps on the ground at sunset, surrounding 
them by shallow basins of oil. The Moths, while moving about to deposit then- 
eggs, flew to the light, and were destroyed in immense numbers among the oil; 
still the few that escaped possessed such powers of reproduction that the damage 
was felt to be very little alleviated. 
The other case occurred in the Hartz Forest, in Germany. During the early 
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