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ROSE LOUSE. 
four at least survived the immersion. “ Many 
years before this experiment/’ says Mr. Curtis, 
“ with a view to destroy the aphides which in- 
fested a plant in my green-house, I immersed, one 
evening, the whole plant, together with the pot in 
which it grew, in a tub of water. In the morning 
I took out the plant, expecting with certainty to 
find every aphis dead ; but to my great surprise 
they soon appeared alive and well. When taken 
from the plant on which they feed, and kept under 
water, they do not survive so long ; their struggling 
in that case perhaps exhausts them sooner. This 
part of the subject might perhaps be pushed much 
further : it is sufficient for our purpose to have 
shown that wet is not so hurtful to them as is gene- 
rally imagined.” 
Mr. Curtis recommends the smoke of tobacco 
beyond every thing else for the destruction of the 
aphides. It is obvious that they can only be de- 
stroyed on a small scale, viz. in a green- house where 
a few plants only, if the gardener is careful, will be 
covered with aphides, and it will be better to re- 
move these into a place where they may be smoked 
separately, than to be at the trouble and expense of 
smoking the whole house. It appears that when 
judiciously applied, the tobacco completely answers 
the purpose without injuring the plant. 
These despoilers of the vegetable kingdom are 
themselves preyed upon by several insects. One 
of their most formidable enemies is the coccinella, 
or common lady-bird. During the severity of win- 
