498 
Soluble  Essence  of  Ginger. 
(  Am.  Jour.  Pharm. 
t      Oct.,  1878. 
been  prepared  from  African  ginger,  which  was  very  dark,  but  not 
of  good  flavor.  His  experience  confirmed  that  of  Mr.  Savage,  that  if 
ginger  were  treated  with  dilute  spirit  in  the  first  instance  the  same  result 
was  obtained  as  by  dissolving  in  strong  spirit  and  then  precipitating  the 
resin.  But  percolation  was  then  apt  to  fail,  because  there  would  be  a 
precipitation  of  a  layer  of  resin  on  the  surface  of  the  marc  which 
prevented  the  further  percolation.  Agitation  with  dilute  spirit  and 
lengthened  maceration  so  as  to  allow  the  resin  to  subside  appeared  to 
be  the  most  practical  and  efficient  mode  of  working. 
Mr.  Hatch  thought  it  probable  that  the  darker  fluid  had  been 
prepared  from  African  ginger. 
Mr.. Groves  asked  if  any  one  knew  the  nature  of  the  resin  which 
was  rejected  by  the  proof  spirit. 
Dr.  Symes  said  he  had  never  examined  it. 
Mr.  Groves  said  he  should  imagine  that  the  essence  of  ginger  as 
made  by  Mr.  Thresh  was  not  quite  so  pungent  as  that  made  by 
maceration,  which  would  contain  the  whole  of  the  resin. 
Professor  Attfield  said  it  had  been  affirmed  that  the  flavor  of  the 
ginger  resided  in  the  oil,  and  the  pungency  in  the  resin.  If  that 
were  so  it  would  follow  that  if  the  resin  were  removed  the  pungency 
would  be  reduced  to  a  similar  extent;  but  then,  as  Mr.  Thresh  hinted, 
there  might  be  two  resins,  one  of  which  was  pungent  and  the  other 
not.  He  should  suggest  that  Mr.  Thresh  examine  the  matter  further,, 
for  he  was  evidently  well  fitted  to  carry  out  an  investigation  of  this 
kind. 
Mr.  Draper  referring  to  the  remark  of  Mr.  Umney  that  oil  of  ginger  was 
quite  a  different  preparation,  said  essence  prepared  from  it  did  not  give 
the  same  results  as  that  obtained  from  the  ginger  itself.  The  oil  of 
ginger  came  from  Germany,  and  was  said  to  be  distilled  from  the 
ginger  root.  No  varieties  were  given,  but  neither  essence  nor  syrup 
of  ginger  could  be  made  from  it.  Why  this  should  be  if  the  whole 
flavoring  resided  in  the  volatile  oil  was  not  quite  clear.  On  the  other 
hand,  it  did  not  seem  to  reside  in  the  resin,  because  with  this  formula 
sixteen  ounces  of  tincture  were  taken  and  added  to  twenty-four  ounces 
of  water,  therefore  necessarily  precipitating  the  whole  resin.  What 
was  left  was  certainly  of  considerable  interest  to  pharmacists  to  deter- 
mine. He  took  rather  an  exceptional  interest  in  the  subject,  and 
should  be  glad  if  it  were  further  investigated. 
