492  Exomination  of  Persian  Insect  Powder,  {^""-ocrissr'™' 
a  precipitate  liaving  the  properties  of  a  soft  resin.  The  alcoholic  solu- 
iion  was  found  to  turn  blue  litmus  paper  red.  A  portion  of  the  benzol 
■extractj  treated  with  a  few  drops  of  potassium  hydrate  solution,  lost 
its  greenish  hue,  changed  to  a  dark  brown,  and  became  readily  soluble 
in  water^  the  solution  forming  a  lather  when  agitated.  This  solution 
yielded  a  precipitate  upon  the  addition  of  a  few  drops  of  acidulated 
water.  A  fresh  portion  of  the  benzol  extract  was  found  to  mix  read- 
ily with  strong  sulphuric  acid,  but  the  addition  of  a  little  water  imme- 
diately caused  a  precipitate.  Nitric  acid  decomposed  the  extract,  leav- 
ing a  yellow  resinous  mass. 
A  iX)rtion  of  the  benzol  extract  was  now  triturated  with  calcined 
magnesia  to  form  a  powder,  of  which  a  few  grains  were  placed 
undemeath  a  fflass  vessel  containino^  a  flv.  The  insect  succumbed  to 
the  poison  in  about  three  minutes.  The  precipitate  obtained  by  dis- 
solving the  benzol  extract  in  alcohol  and  pouring  into  acidulated 
water,  when  reduced  to  a  powder  witli  the  aid  of  magnesia,  also  had 
an  immediate  poisonous  effect.  Tlie  substance  obtained  by  dissolving 
a  portion  of  the  benzol  extract  in  potassium  hydrate  and  ^precipitating 
with  acidulated  water,  was  pulverized  with  magnesia,  and  its  effects 
upon  a  fly  found  to  be  identical  with  those  of  the  two  preceding  sub- 
stances. Now  the  original  powder,  as  left  after  extraction  with  benzol, 
wa«  introduced  beneath  a  glass  containing  a  fly,  the  result  being  no 
apparent  effect  upon  the  insect.  The  powder,  as  left  after  extraction 
with  beiizol,  was  then  percolated  with  95  per  cent,  alcohol,  and  the 
percolate  evaporated  to  dryness.  The  residue,  when  triturated  with 
magnesia  to  form  a  powder,  failed  to  produce  any  poisonous  action  on 
a  fly. 
To  determine  the  presence  of  a  volatile  oil,  a  fresh  portion  of  the 
whole  flowers,  with  enough  water  to  cover,  was  introduced  into  a  retort 
and  a  little  common  salt  added  to  raise  the  boiling  point.  After 
standing  twenty-four  hours,  heat  was  applied,  and  the  mixture  boiled 
until  about  four  fluidounces  had  collected  in  the  receiver.  The  dis- 
tillate contained  no  trace  of  a  volatile  oil. 
Fr<f]»m  what  has  been  said  it  is  evident  that  the  poisonous  principle 
resides  in  the  benzol  extract,  as  the  powder  after  treatment  with  benzol 
no  longer  possesses  any  poisonous  properties.  The  absence  of  alka- 
loids has  been  shown.    Now  what  is  the  nature  of  this  extract? 
An  answer  to  this  question  may  be  found  by  reconsidering  the  pro- 
