Am.  jour.  Pharm.  \       Plants  Used  as  Insecticides. 
January,  19 19.  J 
25 
Summary. 
1.  MM.  Boullay,  pere  et  fils,  should  be  accorded  the  credit  for 
establishing  percolation  as  a  pharmaceutical  process. 
2.  To  MM.  Boutron  and  Robiquet  belongs  the  credit  for  intro- 
ducing percolation  into  the  methods  of  organic  chemistry. 
3.  Guillermond,  Soubeiran  and  Dausse  deserve  special  credit  for 
their  careful  investigations  of  percolation  which  did  much  to  further 
the  establishment  of  the  process  in  pharmacy. 
4.  There  is  no  reliable  evidence  to  show  that  German  apothecaries 
were  acquainted  with  the  principles  of  percolation  before  the  pub- 
lication of  the  investigations  of  French  pharmacists. 
PLANTS  USED  AS  INSECTICIDES.1 
By  R.  C.  Roark. 
In  the  course  of  investigations  on  the  use  of  insect  powder  and 
hellebore  as  insecticides,  the  author  has  noted  many  references  in 
the  literature  to  the  insecticidal  action  of  other  plants.  In  view  of 
the  desirability  of  finding  new  insecticides,  especially  at  the  present 
time  when  the  price  of  arsenicals,  pyrethrum  (insect  powder)  and 
many  other  insecticides  is  so  high,  it  has  seemed  desirable  to  com- 
pile these  statements  and  to  bring  them  to  the  attention  of  ento- 
mologists, pharmacists  and  others. 
Tons  of  the  rhizome  and  rootlets  of  Veratrum  viride  Ait.  are 
used  annually  in  preparing  hellebore,  and  during  the  fiscal  year 
1 91 6-1 7,  insect  flowers  {Chrysanthemum  cinerar ice  folium  Benth. 
&  Hook.),  which,  when  finely  ground,  form  insect  powder,  were 
imported  into  this  country  to  the  value  of  over  $300,000.  In  addi- 
tion, large  amounts  of  larkspur,  sabadilla,  quassia,  red  cedar  shav- 
ings and  tobacco  dust  are  consumed  in  the  preparation  of  insec- 
ticides. It  is  thus  seen  that  there  is  a  large  market  for  plants  as 
insecticides,  and  that  but  a  very  few  species  are  at  present  utilized 
in  this  manner. 
In  view  of  the  large  number  of  plants  possessing  poisonous  prop- 
erties, it  seems  surprising  that  so  few  are  used  commercially  as  in- 
secticides.   Probably  the  majority  of  the  plants  here  listed  have  no 
1  Contribution  from  the  Insecticide  and  Fungicide  Laboratory,  Miscel- 
laneous Division,  Bureau  of  Chemistry,  Department  of  Agriculture,  Wash- 
ington, D.  C. 
