144 
libbig's  extract  of  meat. 
ularly  South  American,  respecting  its  color,  taste,  and  consis- 
tency. 
You  are  probably  aware  of  my  having  accepted  the  office  of 
Director  of  the  Scientific  Department  of  Leibig's  Extract  of 
Meat  Company  (Limited),  and  on  conditions  calculated  to  offer 
to  the  public  a  complete  guarantee  of  the  genuineness  and  purity 
of  the  extract  manufactured  by  that  company. 
One  of  my  former  assistants,  Mr.  Seekamp,  is  the  manager 
of  the  chemical  branch  of  the  manufactory  at  Fray  Bentos  ; 
another  of  my  assistants,  Dr.  Ch.  Finck,  is  acting  at  the  general 
depot  of  the  company.  One  manufactures  the  extract  according 
to  my  special  directions ;  the  other  receives  it  at  Antwerp,  and 
is  bound  to  take  a  sample  of  each  package,  and  to  forward  it  to 
my  laboratory  at  Munich  for  analysis.  The  packages  are  tin 
canisters  of  36  to  45  lbs.  each  ;  the  extract  is  sold  only  after 
being  approved  by  myself.  You  will  perceive  thereby,  that  I 
control  not  only  the  manufacture  according  to  my  process  of  the 
extract  at  Fray  Bentos,  but  also  its  quality  when  sold  by  "  Lie- 
big's  Extract  of  Meat  Company  (Limited),"  and  I  may  safely 
assert,  therefore,  that  the  Fray  Bentos  extract  does  not  contain 
any  gelatine,  or  any  thing  that  can  be  considered  as  such. 
Gelatine  does  not  belong  to  the  composition  of  extract  of 
meat,  and  must,  therefore,  be  excluded  as  much  as  possible ;  it 
gives  more  consistency  to  the  extract,  and  allows,  to  the  detri- 
ment of  buyers,  of  a  larger  percentage  of  water,  and  makes  it 
liable  to  turn  mouldy.  But  the  action  of  tannic  acid,  as  a  reagent, 
might  lead  to  erroneous  conclusions,  against  which  it  is  necessary 
to  guard. 
In  my  little  work  "  On  the  Chemistry  of  Food"  (Taylor  and 
Walton,  London,  1847),  I  say,  p.  141:  "The  portion  of  the 
juice  of  the  flesh  which  is  soluble  in  cold  water,  but  not  in  alco- 
hol, is  precipitated  by  tannic  acid ;  the  precipitate  softens  like 
plaster  in  hot  water,  and  cannot  be  distinguished  from  the  tannate 
of  gelatine,  but  it  differs  from  the  gelatine  by  that  characteristic 
property  of  both,  that  it  does  not  gelatinize  when  concentrated." 
Extract  of  meat,  then,  may  and  does  precipitate  with  tannic  acid, 
even  when  entirely  free  from  gelatine. 
By  the  exclusion  of  gelatine,  the  yield  in  extract  is  naturally 
