128 
HIVE  SYRUP. 
to  pass  through  the  dialyser.  The  first  process  in  which  dilute 
alcohol  had  been  used  succeeded  perfectly,  and  I  have  no  doubt 
will  keep  as  long  as  any  other  syrup  of  the  Pharmacopoeia  ; 
though  sufficient  time  has  not  yet  elapsed  to  test  its  keeping 
qualities.  All  that  is  necessary  is  to  make  a  tincture  of  the 
squills  and  senega  as  directed  in  the  Pharmacopoeia.  Place  this 
solution  in  a  porous  vessel  surrounded  with  water  and  put  aside 
to  dialyse.  After  the  lapse  of  forty-eight  hours  the  water  con- 
tained in  the  outer  vessel  will  be  found  to  have  become  quite 
thick  and  syrupy,  owing  to  the  presence  of  a  large  amount  of 
gummy  substances  which,  first  pass  through  the  porous  diaphragm 
and  dissolving  in  the  surrounding  water,  leave  behind  the  crys- 
talline compounds,  hardly  a  trace  of  which  can  be  found  in  the 
water,  showing  that  in  this  case  the  accuracy  of  the  process  is 
due  to  the  great  difference  in  the  specific  gravity  of  the  two 
liquids,  which  is  also  the  reason  of  the  failure  of  the  aqueous 
decoction.  The  process  is  completed  by  evaporating  the  solution 
contained  in  the  inner  vessel  and  making  it  into  a  syrup  as 
directed  in  the  Pharmacopoeia. 
In  the  course  of  my  experiments  a  few  practical  ideas  sug- 
gested themselves  which  are  absolutely  necessary  to  be  con- 
sidered in  conducting  this  processs.  The  greater  the  difference 
in  the  specific  gravity  of  the  two  liquids  the  more  accurate  will 
be  the  results  obtained.  So  also  as  regards  the  solubility  of  the 
different  salts  held  in  solution.  Light  and  warmth  hasten  the  pro- 
cess of  dialysis  very  materially,  and  care  should  be  taken  to  keep 
the  two  liquids  at  the  same  height  until  the  process  is  completed. 
The  diaphragm  ought  to  be  made  of  the  best  white  porous  ware, 
and  before  using  should  be  soaked  in  dilute  nitric  acid,  and  after- 
wards well  washed  in  water  to  remove  all  soluble  salts.  When 
such  a  vessel  cannot  be  obtained,  a  common  flower-pot  will  an- 
swer instead.  In  conclusion,  it  is  my  belief,  that  owing  to  the 
inaccuracy  of  the  process  of  dialysis  it  can  never  be  very  exten- 
sively used  in  Pharmacy. 
Laboratory,  Dearborn  St.,  Chicago. 
The  Drug.  Cir.  and  Chem.  Gazette. 
