272 
Tin  in  Canned  Foods. 
Am.  Jour.  Pharm. 
May,  1884. 
tin  to  disagree  with  the  system  would  be  too  nasty  to  eat.  Purchasers 
of  food  may  rest  assured  that  the  action  taken  by  this  firm  would  be 
that  usually  followed.  It  is  not  to  the  interest  of  manufacturers  or 
other  vendors  to  offend  the  senses  of  purchasers,  still  less  to  do  them 
actual  harm ;  even  if  no  higher  motive  comes  into  force. 
In  the  early  days  of  canning,  it  is  just  possible  that  the  use  of 
"  spirits  of  salt"  in  soldering  may  have  resulted  in  the  presence  of  a 
little  stannous,  plumbous,  or  other  chloride  in  canned  food ;  but  such 
a  fault  would  soon  be  detected  and  corrected,  and,  as  a  matter  of  fact, 
rosin-soldering  is  to  my  knowledge  more  generally  employed — indeed, 
for  anything  I  know  to  the  contrary,  is  exclusively  employed — in  can- 
ning food.  Any  rosin  that  gained  access  would  be  perfectly  harmless. 
It  is  just  possible,  also,  that  formerly  the  tin  itself  may  have  contained 
lead,  but  I  have  not  found  any  lead  in  the  sheet  tin  used  for  canning 
of  late  years. 
In  conclusion:  1.  I  have  never  been  able  to  satisfy  myself  that  a 
can  of  ordinary  tinned  food  contains  even  a  useful  medicinal  dose  of 
such  a  true  soluble  compound  of  tin  as  is  likely  to  have  any  effect  on 
man.  2.  As  for  the  metal  itself,  that  is  the  filings  or  actual  metallic 
particles  or  fragments,  one  ounce  is  a  common  dose  as  a  vermifuge; 
harmless  even  in  that  quantity  to  man,  and  not  always  so  harmful  as 
could  be  desired  to  the  parasites  for  whose  disestablishment  it  ;s  ad- 
ministered. One  ounce  might  be  contained  in  about  four  hundred- 
weight of  canned  food.  3.  If  a  possibly  harmful  quantity  of  a  soluble 
compound  of  tin  be  placed  in  a  portion  of  canned  food,  the  latter  will 
be  so  nasty  and  so  unlike  any  ordinary  nasty  flavor,  so  "  metallic,"  in 
fact,  that  no  sane  person  will  eat  it.  4.  Respecting  the  globules  of 
solder  (lead  and  tin)  that  are  occasionally  met  with  in  canned  food,  I 
believe  most  persons  detect  them  in  the  mouth  and  remove  them,  as 
they  would  shots  in  game.  But  if  swallowed  they  do  no  harm.  Pereira 
says  that  metallic  lead  is  probably  inert,  and  that  nearly  a  quarter  of 
a  pound  has  been  administered  to  a  dog  without  any  obvious  effects. 
He  goes  on  to  say  that  as  it  becomes  oxidized  it  occasionally  acquires 
activity,  quoting  Paulini's  statement  that  colic  was  produced  in  a 
patient  who  had  swallowed  a  leaden  bullet.  To  allay  alarm  in  the 
minds  of  those  who  fear  they  might  swallow  pellets  of  solder,  I  may 
add  that  Pereira  cites  Proust  for  the  assurance  that  an  alloy  of  tin  and 
lead  is  less  easily  oxidized  than  pure  lead.  5.  Unsoundness  in  meat 
does  not  appear  to  promote  the  corrosion  or  solution  of  tin     I  have 
