534 
Assay  of  Jalap. 
Adj.  Jour.  Pharm. 
Oct.,  1892. 
solubility  of  jalap  resin  in  amylic  alcohol,  and  the  comparatively 
small  solubility  of  amylic  alcohol  in  water,  and  is  as  follows  :  One 
gramme  of  powdered  jalap — free  trom  agglutinated  lumps — is 
placed  in  a  suitable  bottle,  and  20  cc.  of  amylic  alcohol  are  added 
and  shaken  well  from  time  to  time.  After  a  few  hours  strain  the 
liquid  off  through  a  little  cotton  wool  into  a  glass  separator,  wash 
out  the  bottle  with  5  cc.  amylic  alcohol  and  place  the  washings  on 
the  marc  in  the  funnel,  repeat  with  5  cc.  more  if  necessary  so  as  to 
ensure  the  presence  of  all  the  resin  in  the  separator. 
Now,  shake  up  the  amylic  solution  of  the  resin  with  small  quanti- 
ties of  water  at  500  C.  (equal  measures  of  hot  and  cold  water  will 
do),  set  aside  for  the  liquids  to  separate,  remove  the  lower  aqueous 
layer,  and  repeat  the  washing  with  water  until  nothing  more  of  a 
non-resinous  nature  is  removed.  Afterwards  transfer  the  solution 
of  the  resin  to  a  weighed  dish  containing  10  cc.  distilled  water,  wash 
out  the  separator  with  a  little  amylic  alcohol,  placing  the  washings 
in  the  dish,  evaporate  on  a  water-bath  in  the  usual  way,  and  when 
dry,  weigh. 
The  advantages  of  this  method  are  : 
(1)  That  less  of  the  water-soluble  matter  is  removed  than  by  the 
official  process. 
(2)  After  careful  treatment  with  the  amylic  alcohol  no  resin 
remains,  rectified  spirit  dissolving  from  the  residue  only  water  solu- 
ble matters  and  no  resin. 
(3)  It  is  a  cheap  process  because  common  fusel  oil  once  distilled 
can  be  used,  but  in  this  case  more  water-soluble  matter  is  removed 
and  more  washing  required. 
The  use  of  the  water  when  evaporating  off  the  amylic  alcohol  is 
to  prevent  the  alcoholic  solution  creeping  over  the  sides  of  the  dish 
and  consequent  loss  of  resin. 
As  the  vapor  of  amylic  alcohol  is  not  a  pleasant  one  to  inhale,  the 
evaporation  is  best  conducted  under  a  good  flue. 
An  examination  of  many  samples  of  commercial  powdered  jalap 
sold  in  Birmingham  and  district  confirms  the  often  expressed 
opinion  that  the  official  standard  of  10  per  cent,  of  resinous  con- 
stituents is  too  high  at  the  present  date. — Phar.  Jour,  and  Ivans., 
August  6,  1892,  p.  107. 
