20 
Adulteration  Notes,  etc. 
J  Am.  Jour.  Pharm. 
I     Jan.  1,  1874. 
pure  chrysophanic  acid."  (Batka).  Being  thus  changed  in  the  exte- 
rior insect-perforated  and  spongy  portions  of  the  root  into  amorphous 
resins  soluble  in  chloroform,  we  may  trace  in  imagination  the  cause 
of  the  deep  yellow  stain  given  by  deteriorated  roots. 
The  formulae  slightly  bear  out  this  theory,  that  of  chrysophanic 
acid  given  by  Rochleder  and  Heldt,  who  seem  to  have  obtained  it 
from  the  lichen  Parmelia  parietina,  is  C10H8O3,  and  that  given  by 
Thann,  who  procured  it  from  rhubarb,  is  C17H10O2,  while  that  of 
phaeoretin  is  stated  as  C16H10O7,  and  erythroretin  C19H1807  by 
Gmelin,  whose  formula  for  chrysophanic  acid  is  CuH10O3  (altered  to 
new  notation). 
Chrysophanic  acid  gives  with  caustic  alkalies  a  red  color,  and 
erythroretin  a  bright  purple,  as  may  be  observed  by  touching  the 
yellow  rhubarb  stain  with  solution  of  potash. 
With  a  substance  such  as  rhubarb,  varying  in  chemical  as  well  as 
physical  characteristics,  great  care  must  be  exercised  before  pro- 
nouncing definitely  upon  any  test  for  distinguishing  between  the  va- 
rieties, depending  upon  such  a  minute  difference  as  depth  of  tint. 
While  putting  forward  this  method  of  identifying  European  in  pres- 
ence of  fine  Eastern  grown  rhubarb  with  some  degree  of  confidence, 
having  found  unvarying  results  from  the  examination  of, well-nigh  one 
hundred  specimens,  it  is  much  to  be  desired  that  others  would  take 
up  the  subject  and  confirm  or  discredit  the  results  I  have  obtained. 
It  is  necessary  that  day-light  be  used  in  following  these  tests,  as 
gas,  or  other  common  artificial  light  being  yellow,  the  delicate  tints 
are  thereby  rendered  invisible. 
Turmeric  in  Aromatic  Chalk  Powder. — As  with  bright-colored  rhu- 
barb, so  it  is  not  uncommon  to  hear  turmeric  suggested  as  the  cause 
of  the  fine  yellow  color  of  some  makes  of  aromatic  chalk  powder. 
This  and  other  powders  containing  saffron  may  be  tested  exactly  in 
the  same  manner  as  above  directed  for  rhubarb.  Polychroite,  or  cro- 
cin,  the  coloring  principle  existing  to  the  extent  of  50  or  60  per  cent. 
(Pereira)  in  hay  saffron  is  quite  insoluble  in  chloroform,  which  only 
dissolves  out  a  small  quantity  of  yellowish  oil.  Aromatic  chalk  pow« 
der  should  therefore  give  no  yellow  stain  with  chloroform ;  a  very 
small  proportion  of  turmeric  will  thus  be  at  once  detected. 
The  saffron  yellow,  which  may  be  obtained  by  using  alcohol  instead 
of  chloroform,  unlike  that  of  turmeric,  is  changed  to  green  by  con- 
