3^5 
ronlainlng  24  young  growing  basil  plants  from  4 to  I 2 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  20lh  twelve  mosquitoes 
were  liberated  in  case  2.  On  the  21st  no  observations  were  made, 
but  on  the  22nd  seven  were  found  in  case  i perched  over  the  top 
jof  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.  d'he  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  attac'ks  of  hungry  mosquitoes. 
'Fhe  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  6th  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,  d'hree  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  any,  the  fumes  of  basil  leaves  when  burnt  had  on  mosquitoes. 
Cases  containing  mosquitoes  were  hung  on  the  wall  and  in  the 
middle  of  a small  ro  >m  containing  a little  over  i,ooo  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  aw^ay  mos- 
quitoes, and  are  not  to  be  rdied  on  as  a substitute  for  the  mosquito 
net. 
2.  Fresh  basil  leaves  hive  no  prejudicial  effect  on  mosquitoes 
when  placed  in  close  contact  w ith  them. 
3.  The  fumes  of  burnt  basil  leaves  have  a stupifying  and  even- 
tually a destructive  elfect  on  mosquitoes,  but  to  obtain  this  actioii 
a degree  of  saturation  of  the  air  is  necessary  which  renders  it  im- 
