Am™yfiS4f*m*}  Contributions  to  Pharmacy.  361 
RECENT  CONTRIBUTIONS  TO  PHARMACY. 
NOTE  ON  LEMON  AND  ORANGE  PEEL. 
In  a  paper  before  the  Society  of  Public  Analysts,  E.  G.  Clayton 
(The  Analyst,  19,  134),  has  noticed  that  when  orange  peel  is 
moistened  with  strong  hydrochloric  acid,  its  color  changes  from 
yellow  to  a  rich,  dark  green ;  lemon  rind,  similarly  treated,  retains 
its  hue,  or,  at  most,  assumes  a  dingy,  yellowish-brown  tint.  A  con- 
venient and  simple  chemical  test,  therefore,  which  will  distinguish 
between  small  fragments  of  lemon  and  orange  peel  is  to  touch  them 
with  a  glass  rod  previously  dipped  in  hydrochloric  acid.  The  diluted 
acid  will  answer  the  purpose,  but  the  reaction  is  slower.  A  few 
minutes'  exposure  to  hydrochloric  acid  gas  will  effect  this  change  in 
the  pigment  of  orange  peel.  The  color  of  lemon  rind  is  unaffected. 
The  shades  of  green  developed  by  dilute  hydrochloric  acid  are 
deepest  in  the  cases  of  Mercia,  Denia  and  Florida  oranges  ;  of  mode- 
rate intensity  with  Jaffa  and  "  blood  "  oranges ;  and  feeble  with 
Valencia  and  Tangerine  oranges.  This  statement  also  applies  to 
the  reactions  with  strong  hydrochloric  acid,  except  that  the  color  of 
Tangerine  orange  peel  with  the  strong  acid  is  perhaps  more  intense 
than  that  observed  with  any  of  the  other  varieties  of  the  fruit. 
The  peel  of  the  lime  behaves,  with  hydrochloric  acid,  like  lemon 
rind. 
Mr.  Hehner  remarked  that  it  was  not  at  all  an  infrequent  occur- 
rence for  lemon  and  other  peels  to  be  artificially  colored.  He 
thought  that  at  present  too  implicit  reliance  should  not  be  placed 
on  this  test  in  the  case  of  candied  peel. 
DETECTION  OF  COPPER  IN  GREEN  PRESERVES. 
A.  Tschirch  (Zeit.  anal.  Chem.  34,  103)  gives  the  following  process 
for  determining  whether  the  green  color  in  certain  preserved  foods 
is  due  to  chlorphyll  or  to  copper  phyllocyanate. 
An  alcoholic  extract  is  evaporated  to  dryness,  the  residue  washed 
with  water,  and  then  treated  with  concentrated  hydrochloric  acid. 
Pure  chlorphyll  gives  a  deep  blue  solution,  and  a  residue  soluble  in 
ether  with  a  brown  color,  but  hydrochloric  acid  dissolves  only  a 
small  amount  of  a  yellow  substance  when  copper  phyllocyanate  is 
preserit,  and  the  residue  dissolves  in.  alcohol  with  a  green  color. 
If  dilute  hydrochloric  acid  is  added  to  the  alcoholic  solution,  a 
green  color  indicates  coppei;,  used  in  its  absence,  the  mixture  is 
yellow. 
