A  October, Tsh96.rm,l    Recent  Contributions  to  Pharmacy.  569 
tion.  The  insoluble  residue  is  treated  with  a  few  drops  of  strong 
nitric  acid,  dried  and  ignited.  The  ignited  mass  is  treated  with 
strong  hydrochloric  acid,  and  the  filtrate  added  to  the  first  solution, 
which,  after  concentrating  to  about  30  c.c.  to  40  ex.,  is  placed  in  a 
weighed  platinum  dish  and  the  copper  precipitated  with  pure  zinc. 
If  the  copper,  after  weighing,  has  not  a  pure  color,  it  is  dissolved  in 
a  little  nitric  acid,  made  up  to  a  known  quantity  and  determined 
colorimetrically  in  an  ammoniacal  solution. 
In  this  way  the  following  results  were  obtained : 
Parts  of  Copper 
in  10,000  of  the 
Substance. 
Oysters  : 
Portuguese   2  94 
Whitstable   181 
Dutch   i-8i 
Plymouth   3"°3 
Cocoa  : 
Pure  cocoa  (free  from  husk)                       .   0*47 
Cocoa  containing  sugar  and  starch   0*58 
Brandy :  ^ . 
Sample  No.  1   0-05 
"         "2   O'OI 
<f3   0-04 
"          "4   O'OI 
Whisky    0*04 
Preserved  Peas : 
Sample  No.  1    1*44 
"2   1-14 
"3   1*10 
"   4   0-57 
"    5    0-54 
"       "6   1*40 
"    7   0-95 
"8   095 
"9   i-25 
"10   0-95 
"11   070 
These  results  and  others  show  that  the  amount  of  copper  in  pre- 
served peas  varies  considerably.  Some  of  the  samples  were  guar- 
anteed not  to  have  been  treated  with  a  copper  salt. 
Some  results  obtained  by  Vedrodi's  method  are  here  appended 
for  comparison : 
