496 
Soluble  Essence  of  Ginger. 
f  Am.  Jour.  Pharm. 
t      Oct.,  1878. 
pound  of  resin  and  magnesia.  I  had  suspected  that  the  resin  left  in 
solution  differed  from  that  removed,  but  upon  evaporating  the  soluble 
essence  and  examining  the  resinous  residue  I  could  detect  no  difference 
between  them  ;  moreover  when  dissolved  in  spirit,  diluted  and  shaken 
with  magnesia,  most  of  it  was  removed  from  solution,  and  the 
magnesia  compound  resembled  that  first  separated. 
I  have  since  found  that  calcium  sulphate,  calcium  carbonate  and 
charcoal  powder  are  equally  efficacious  in  removing  the  excess  of  resin, 
but  the  resulting  solution  is  in  all  cases  much  paler  in  color,  and  prob- 
ably when  charcoal  is  used  the  odor  may  not  be  so  strong.  These  no 
doubt  act  mechanically,  causing  the  aggregation  of  the  resin  precipitated 
by  the  water  \  hence  it  is  probable  that  any  fine  inert  powder  will 
answer  as  well  as  the  magnesia. 
A.syrup  made  by  mixing  equal  quantities  of  strong  simple  syrup  and 
soluble  essence  is  very  suitable  for  using  with  gazogenes,  and  a  weaker 
syrup  might  with  advantage  replace  the  unsightly  preparation  of  the 
Pharmacopoeia. 
The  belief  that  this  subject  would  be  of  interest  to  many  pharma- 
cists, and  that  the  results  of  my  imperfect  investigation  would  be  of 
value  to  others,  must  be  my  apology  for  troubling  the  Conference  with 
this  paper. 
Specimens  of  soluble  essence  and  of  syrup  made  therefrom  are  upon 
the  table,  at  the  service  of  any  member  who  would  like  to  examine 
them. — Phar.  your,  and  Trans.,  Aug.  31,  1878. 
SOLUBLE  ESSENCE  OF  GINGER.1 
BY  B.  S.  PROCTOR. 
Commercial  samples  have  no  great  alcoholic  strength. 
Essence  of  ginger  made  with  strong  spirit  and  diluted  with  water 
continues  milky  for  a  long  time. 
The  same  mixed  with  a  little  alum  or  sulphuric  acid  becomes  clear 
after  standing  some  time  (a  week  or  two  ?).  The  quantity  of  alum  or 
acid  requisite  is  not  sufficient  to  impart  any  taste  to  the  essence  pro- 
duced, and  may  be  got  rid  of  (the  acid  most  completely)  by  mixing 
with  pure  carbonate  of  lime  and  filtering.  A  clear,  pungent,  aromatic 
essence  is  thus  produced,  which  turns  slightly  opalescent  when  mixed 
with  water. 
1  Read  before  the  British  Pharmaceutical  Conference. 
