270 
Tin  in  Canned  Foods. 
Am.  Jour.  Pharm. 
May,  1884. 
the  past  two  or  three  months  I  have  examined  sixteen  varieties  of 
canned  food  for  metals,  with  the  following  results : 
Decimal  parts  of  a  grain 
Name  of  article  of  tin  (or  other  foreign 
examined.  metal)  present  in  a 
quarter  of  a.  pound. 
Salmon   none 
Lobsters   none 
Oysters   0-004 
Sardines   none 
Lobster  paste   none 
Salmon  paste   none 
Bloater  paste   0-002 
Potted  beef   none 
Potted  tongue   none 
Potted  "  Strasbourg"   none 
Potted  ham   0*002 
Luncheon  tongue   0*003 
Apricots   0-007 
Pears     0*003 
Tomatoes   0*007 
Peaches   0*004 
These  proportions  of  metal  are,  I  say,  undeserving  of  serious  notice. 
I  question  whether  they  represent  more  than  the  amounts  of  tin  we 
periodically  wear  off  tin  saucepans  in  preparing  food — a  month  ago  I 
found  a  trace  of  tin  in  water  which  had  been  boiled  in  a  tin  kettle — 
or  the  silver  we  wear  off  our  forks  and  spoons.  There  can  be  little 
doubt  that  we  annually  pass  through  our  systems  a  sensible  amount 
of  such  metals,  metallic  compounds,  and  other  substances  that  do  not 
come  under  the  denomination  of  food ;  but  there  is  no  evidence  that 
they  ever  did  or  are  ever  likely  to  do  harm  or  occasion  us  the  slightest 
inconvenience.  Harm  is  far  more  likely  to  come  to  us  from  noxious 
gases  in  the  air  we  breathe  than  from  foreign  substances  in  the  food 
we  eat. 
But  whence  come  the  much  less  minute  amounts  of  tin — still  harm- 
less be  it  remembered — which  have  been  stated  to  be  occasionally 
present  in  canned  foods?  They  come  from  the  minute  particles  of 
metal  chipped  off  from  the  tin  sheets  in  the  operations  of  cutting,  bend- 
ing or  hammering  the  parts  of  the  can,  or  possibly  melted  off  in  the 
operations  necessary  for  the  soldering  together  of  the  joints  of  the  can. 
Some  may,  perhaps,  be  cut  off  by  the  knife  in  opening  a  can.  At  all 
events  I  not  unfrequently  find  such  minute  particles  of  metal  on  care- 
