Amse?t.MSarm*}  Toxic  Principle  of  Pyrethrum  Flowers.  457 
charged  with  essential  oil,  had  been  collected.  After  filtration 
through  a  moistened  filter  the  filtrate  was  shaken  with  ether,  the 
ethereal  solution  separated,  filtered  and  evaporated  at  a  temperature 
below  300  C,  until  there  remained  in  the  capsule  a  small  quantity 
of  water  and  a  few  small  green  drops.  The  aqueous  portion, 
separated  by  means  of  a  moistened  filter,  had  an  odor  of  black  tea, 
was  slightly  acid  to  litmus,  but  did  not  appear  to  incommode 
insects.  The  green  drops  were  toxic,  but  did  not  contain  any  alka- 
loid. 
In  a  second  operation  the  distillate  was  treated  under  the  same 
conditions  with  chloroform,  which  left  upon  evaporation  an  acid  and 
toxic  residue. 
The  same  acid  compound  was  also  obtained  under  other  condi- 
tions. For  instance,  the  powder  was  submitted  to  displacement 
with  amylic  alcohol,  the  amylic  liquor  shaken  with  water  in  a 
separator,  the  aqueous  layer  removed,  filtered  and  neutralized  with 
baryta  water ;  then  heated  on  a  water  bath  to  drive  off  the  amylic 
alcohol  dissolved  in  the  water,  after  which  it  was  filtered  and  the 
baryta  saturated  with  sulphuric  acid  in  excess.  Finally,  the  liquid 
was  shaken  with  ether,  and  upon  evaporation  of  the  ethereal  liquid 
there  was  obtained  a  greenish  acid  residue,  partially  soluble  in 
water  and  giving  a  solution  having  insecticidal  properties.  If 
instead  of  amylic  alcohol  ordinary  alcohol  were  used  the  same 
result  was  arrived  at. 
In  another  experiment  the  pyrethrum  powder  was  moistened  with 
alcohol  containing  a  little  acid,  then  dried  and  afterwards  exhausted 
with  ether.  The  ethereal  solution  was  treated  with  ammonia  water, 
and  the  latter  separated,  filtered  and  evaporated  to  dryness.  The 
residue  was  redissolved  in  water,  and  after  filtration  it  contained  in 
solution  the  ammoniacal  salt  of  the  toxic  acid  of  pyrethrum  powder. 
The  solution  was  toxic  to  insects,  and  gave  with  silver  nitrate, 
neutral  lead  acetate,  or  neutral  lead  acetate  in  alcoholic  solution  an 
abundant  precipitate;  with  barium  nitrate,  calcium  sulphate  or  ferric 
chloride  no  precipitate. 
In  another  operation  200  grams  of  powdered  pyrethrum  flowers 
v/as  displaced  with  a  litre  of  chloroform.  The  solvent  was  recov- 
ered by  distillation,  and  the  residue  was  worked  up  with  water  to 
free  it  from  an  inactive  substance.  The  extract  was  afterwards 
taken  up  with  900  alcohol,  and  the  alcoholic  liquid  filtered  and 
