A  August,  \h9T'  >     taking  Money  out  of  "Bugs."  525 
destroys  the  vitality  of  the  eggs,  gasoline  being  less  efficient, 
apparently  because  of  its  greater  volatility. 
Coal-tar-creosote  emulsions,  i.  e.,  preparations  of  the  type  of 
creolin,  are  100  per  cent,  effective  when  used  undiluted, 
but  are  not  very  valuable  when  diluted,  as  they  must  be  in 
practical  application. 
Mercuric  chloride,  in  6  per  cent,  solution  and  in  powder,  is 
100  per  cent,  effective.    It  is  too  poisonous,  especially  in 
the  powder  form,  for  promiscuous  use. 
Pyrethrum  powder  is  very  effective.    If  the  powder  contains 
much  stem,  it  is  worthless. 
Turpentine  oil  is  100  per  cent,  effective. 
Sabadilla  seed  in  powder  is  100  per  cent,  effective.    This  is 
often  used  for  destroying  body  lice,  but  is  not  generally 
known  to  have  value  in  destroying  bedbugs. 
Sulphur,  when  burned,  under  proper  conditions,  at  the  rate 
of  one  pound  to  a  thousand  cubic  feet  of  space,  is  effective 
against  both  bugs  and  eggs. 
Among  substances  popularly  supposed  to  be  of  value,  but  which 
tests  prove  to  be  worthless  or  nearly  so,  are : 
Paraformaldehyde,  even  when  used  in  the  proportion  of  two 
and  one  quarter  pounds  to  one  thousand  cubic  feet  of  space. 
Formaldehyde,  diluted  1— 14  and  used  as  a  spray. 
Sodium  fluoride. 
Paris  Green. 
When  used  against  roaches : 
Sodium  fluoride  is  100  per  cent,  effective,  and,  even  diluted 
with  inert  powders  to  18  per  cent,  strength,  is  still  very 
effective. 
Hydrocarbon  oils,  as  gasoline  and  kerosene,  and  preparations 
consisting  largely  of  the  same,  are  effective  if  they  come 
in  contact  with  the  insect.  Roaches,  however,  are  not 
obliging  enough  to  come  out  of  hiding  in  any  considerable 
numbers  except  at  night  and  when  left  alone.    For  this 
~  reason,  the  use  of  such  substances  is  in  the  same  category 
as  catching  a  bird  by  putting  salt  on  its  tail. 
Among  substances  popularly  supposed  to  be  effective,  but  which 
tests  failed  to  prove  as  efficient  as  the  above  are : 
Borax,  partially  effective,  but  slow. 
Phosphorus  pastes,  partially  effective,  but  slow. 
