containing 24 young growing basil plants from 4 to 12 inches high 
were placed in case No. 1 along with half a dozen ripe bananas. 
In case No. 2 no food was placed. On the 20th twelve mosquitoes 
were liberated in case 2. On the 21st no observations were made, 
but on the 22nd seven were found in case 1 perched over the top 
of the plants, three were found in empty case 2 while two had dis- 
appeared. On the 24th there were still seven in case No. I and 
only one in case 2. The experiment was then terminated. 
This experiment shows conclusively that the presence of a num- 
ber of basil plants is not sufficient to deter a hungry mosquito 
from seeking food, and it may safely be inferred that three or four 
plants round a bed would not be sufficient to protect a sleeping 
individual from the attacks of hungry mosquitoes. 
The second series of experiments was directed to ascertaining 
whether close contact with basil leaves was fatal to mosquitoes. 
A quantity of fresh basil leaves was placed in a small stoppered 
bottle and in another as a control, a quantity of fresh rose leaves. 
On the 5th three mosquitoes were placed in each, and the stoppers 
firmly fixed down. On the bth'all the mosquitoes were lively and 
flew about when the bottles were shaken. The mosquitoes fre- 
quently rested on the basil leaves. 8th — The three in the basil 
bottle were alive but somewhat sluggish. Those in the rose bottle 
were dead. Three days close contact with basil leaves is therefore 
not sufficient to kill mosquitoes. 
The experiment was repeated using hibiscus leaves as a control, 
with similar results. The mosquitoes lived four days without food 
in contact with basil leaves. 
The object of the next experiments was to ascertain what effect, 
if anv, the fumes of basil leaves when burnt had on mosquitoes. 
Cases contdining mosquitoes were hung on the wall and in the 
middle of a small ro >m containing a little over 1,000 cubic feet of 
air, and quantities of dried and powdered leaves varying from 4 oz. 
to a pound were burnt on a brazier filled with lived charcoal. It 
was found that when the atmosphere reached a degree of saturation 
which made the air extremely uncomfortable to breathe, prolonged 
exposure of an hour or an hour and a half undoubtedly had a stupi- 
fying effect on the mosquitoes and they were found lying in the 
bottom of the cages apparently dead. After exposure to fresh air, 
however, the majority recovered. 
The conclusions- may be briefly summarised as follows : — 
1. Growing plants have little or no effect in driving away mos- 
quitoes, and are not to be relied on as a substitute for the mosquito 
net. 
2. Fresh basil leaves h >ve no prejudicial effect on mosquitoes 
when placed in close contact with them. 
3. The fumes of burnt basil leaves have a stupifying and even- 
tually a destructive effect on mosquitoes, but to obtain this action 
a degree of saturation of the air is necessary which renders it irn- 
'XA 
