364 
Colored  Insect  Powder. 
(  Am.  Jour.  Pharm, 
I      July,  1883. 
pected  powder  placed  in  the  centre  and  pressed  compactly  down  with 
a  piece  of  paper  or  a  spatula.  Chloroform  (or  other  menstruum)  is 
then  carefully  dropped  from  a  pipette  on  the  centre  of  the  powder  till 
it  has  moistened  all  and  extended  some  distance  beyond  the  powder. 
The  paper  is  then  allowed  to  dry^  wiped  free  of  the  powder,  and  the 
stain,  if  any,  tested  by  suitable  reagents. 
Treated  in  this  manner  the  genuine  powder  yields  a  slight  yellow  color 
to  the  paper;  but  No.  12,  and  in  less  degree  No.  10,  gave  a  very  distinct 
stain,  which  an  atom  of  boracic  acid  and  a  drop  of  HCl  at  once  iden- 
tified as  due  to  turmeric.  The  stain  from  genuine  powder  becomes 
bluish-green  with  nitric  acid,  brownish  with  sulphuric,  and  only  exhi- 
bits a  slight  darkening  with  potash  solution.  The  turmeric  stain 
becomes  reddish  brown  with  nitric  acid,  dark  brown  with  sulphuric 
acid  or  potash.  Fustic  seems  to  yield  nothing  to  chloroform,  but  a 
yellow  stain  obtained  with  alcohol  becomes  a  distinct  brown  with  nitric 
acid,  and  shows  little  change  with  sulphuric  acid  or  potash.  Solution 
of  a  ferric  salt  strikes  a  bluish  black  both  with  the  fustic  and  pyre- 
thrum  stain  obtained  with  alcohol. 
When  fustic  is  boiled  for  some  time  in  water  wnth  zinc  and  sulphu- 
ric acid  the  solution  gradually  assumes  a  bright  red  color,  owing  to  the 
transformation  of  one  of  the  coloring  principles,  morintannic  acid,  into 
phloroglucin  and  machromine. 
The  flowers  of  Pyrethrum  cineraricefolmm  treated  in  the  same  fashion 
sliow  no  change,  but  I  have  been  unable  to  get  tliis  very  promising 
reaction  to  indicate  distinctly  anything  under  20  per  cent,  of  fustic  in 
insect  powder,  although  I  am  hopeful  that  an  improved  method  may 
yet  result  in  greater  delicacy. 
No.                          Percentage  of  ash.  No.                       Percentage  of  ash. 
1  6-2  7  10-5 
2  7-1  8   9-6 
3  6-  9   9-2 
4  6-8  10   8-0 
5  6-2  11   9-4 
6  6-2  12   6-0 
The  above  table  shows  the  percentage  of  ash  yielded  by  the  twelve 
samples,  and,  comparing  that  with  the  names  given  by  the  vendors, 
little  relation  will  be  observed  between  them.  From  more  exact  anal- 
ysis I  take  the  first  six  to  be  genuine  powders,  with  the  exception  of 
No.  6,  which  has  a  suspicion  of  some  dye  wood,  which  I  have  not  yet 
