494 
Preservation  of  Food. 
f  Am.  Jotjr.  Pbaem. 
\     Nov.  1,  1873. 
poration  of  a  moderate  quantity  of  powdered  tragacanth  affords  the 
desired  and  required  assistance  by  which  the  mixture  can  be  made  to- 
assume  an  adhesive,  compact  and  uniform  character,  and  thus  be 
easily  applied  upon  the  plaster,  which  by  aid  of  its  exposed  margin, 
will  stick  firmly  and  securely  to  the  position  in  which  it  is  placed  on 
the  skin. 
Other  plasters  can  be  produced  by  the  aid  of  powdered  tragacanth, 
whereby  large  quantities  of  oil  or  extract  can  be  employed,  when 
spread  upon  sheets,  with  an  adhesive  margin.  In  every  case,  the 
extract  is  first  liquefied  with  water  and  a  small  proportion  of  gly- 
cerin, the  oily  substance  added,  then  thickened  with  powdered  tra- 
gacanth, and  finally  spread  upon  any  desirable  base,  with  an  adhe- 
sive margin. —  The  Pharmacist,  Au$u$ty  1873. 
ON  THE  PRESERVATION  OF  FOOD. 
By  S.  P.  Sharples,  S.  B. 
One  of  the  surest  signs  of  advance  in  civilization  is  the  increased 
attention  that  is  being  paid  to  the  subject  of  furnishing  improved 
articles  of  food  for  the  masses,  at  such  a  rate  and  in  such  quantities 
that  the  use  of  fresh  fruit  and  vegetables  out  of  season  is  no  longer 
confined  to  the  tables  of  the  wealthy.  One  of  the  earliest  efforts  of 
man,  when  emerging  from  the  primitive  savage  state,  is  to  provide 
food  for  the  morrow,  for  so  long  as  he  is  dependent  on  the  daily  chase 
for  his  means  of  sustenance  he  can  make  but  little  progress,  andr 
moreover,  the  tribes  who  live  from  hand  to  mouth  lead  but  a  preca- 
rious existence — feasting  to-day  and  starving  to-morrow. 
One  of  the  earliest  methods  of  preserving  food  is  by  simply  drying 
it,  either  in  the  open  air  or  by  aid  of  the  smoke  of  a  smoldering  fire. 
This  latter  method  furnishes  a  curious  instance  of  the  way  that  sci- 
ence is  so  often  anticipated  in  her  methods  by  those  who  know  noth- 
ing of  her  principles.  The  creasote  of  the  smoke  acts  as  the  preser- 
vative. Carbolic  acid,  a  nearly  allied  substance,  is  recognized  to-day 
as  one  of  our  best  preservative  agents,,  although  creasote  still  holds 
its  own.  The  objections  to  drying  meats  are  that  the  flesh  is  ren- 
dered more  or  less  unpalatable,  and,  unless  it  receives  some  previous- 
treatment,  is  apt  to  putrefy  somewhat  in  the  operation.  The  most 
common  method  of  treatment  employed  is  to  either  soak  it  in  a  strong 
solution  of  common  salt,  or  to  rub  it  with  a  mixture  of  common  salt, 
