568  Recent  Contributions  to  Pharmacy.  { 
Am.  Jour.  Pkarm. 
October,  1896. 
The  author  concluded  that  those  syrups  made  by  allowing  the  iodine 
and  tannin  to  react  on  each  other,  formed  a  true  iodotannic  syrup, 
v/hile  in  those  in  which  all  the  ingredients  were  mixed  at  once,  the 
solution  of  the  iodine  was  effected  by  the  inversion  of  a  portion  of 
the  sugar. 
ON  THE    OCCURRENCE    OF    QUERCETIN    IN    THE    OUTER    SKINS  OF  THE 
BULB  OF  THE  ONION  (ALLIUM  CEPA). 
Perkin  and  Hummel,  in  the  Proc.  Chem.  Society,  1896,  p.  144, 
report  on  the  occurrence  of  quercetin  in  the  outer  skins  of  the  bulb 
of  the  onion  (Allium  cepa). 
It  was  stated  that  Zeuch  {Parben  und  Farbenk'unde,  1825,  1,  434) 
has  described  the  dyeing  properties  of  these  skins.  The  authors 
obtained  the  coloring  matter  in  the  form  of  glistening  yellow  nee- 
dles, of  the  formula  C15H10O7,  which  yielded  compounds  with  mine- 
ral acids ;  the  sulphuric  acid  compound  C15H10OT,  H2S04  was  anal- 
yzed. On  acetylation,  a  compound,  C15H507(C2H30)5,  forming 
colorless  needles,  melting  point  190-1910,  was  obtained,  and,  by 
decomposition  with  fused  alkali,  phloroglucin  and  protocatechuic 
acid  formed  the  principal  products.  With  mordants  it  dyed  shades 
similar  to  those  given  by  quercetin,  the  coloring  matter  of  quercitron 
bark,  and  was  thus  proved  to  be  identical  with  this  substance. 
Comparative  dyeing  experiments  showed  that  the  coloring  mat- 
ter of  onion  skins  was  quite  equal  to  that  of  such  well-known  dye- 
stuffs  as  old  fustic  and  quercitron  bark. 
THE  DETECTION  OF  COPPER  IN  VEGETABLE  SUBSTANCES. 
Messrs.  Paul  and  Cownley,  in  the  Pharmaceutical  Journal  of 
June  6,  1896,  refer  to  a  paper  by  Dr.  Victor  Vedrbdi,  in  the  Chemiker 
Zeitung  of  May  16,  1896,  in  which  the  accuracy  of  the  method  of 
Prof.  Lehmann  for  the  determination  of  copper  in  vegetable  sub- 
stances is  questioned. 
The  authors,  after  pointing  out  the  liabilities  to  error  in  both  the 
methods  of  Dr.  Vedrodi  and  Prof.  Lehmann,  give  one  of  their  own, 
which  they  consider  reliable.  It  consists  in  carbonizing  about  100 
grammes  of  the  material  in  platinum,  extracting  the  ash  with  strong 
hydrochloric  acid,  filtering  through  an  acid-washed  filter  into  a 
porcelain  dish  and  washing  the  filter  with  hot  water  into  this  solu- 
