AmAJu°gU,r'i8>7h8?rm'}  Commercial  Extracts  and  Resins  of  Jalap.  371 
ASSAY  OF  COMMERCIAL  EXTRACTS  AND  RESINS  OF 
JALAP. 
By  Chas.  D.  Farwell,  Ph.G. 
[From  an  Inaugural  Essay.) 
The  examination  of  a  few  commercial  extracts  and  resins  of  jalap, 
for  the  purpose  of  comparing  them  in  regard  to  purity  and  the  relative 
amount  of  medicinally  active  constituents  contained  therein,  was  con- 
ducted in  the  following  manner: 
One  gram  of  each  extract  was  dried  over  sulphuric  acid  and  weighed^ 
to  ascertain  the  amount  of  moisture  present.  Ten  grams  of  each 
extract  were  exhausted  by  water,  and  the  residual  resins,  after  being 
dried  and  weighed,  were  treated  with  stronger  ether  to  separate  the 
soft  from  the  hard  portion.  The  etherial  solutions,  being  allowed  to 
evaporate,  yielded  the  soft  resins,  which  were  weighed  and  dissolved  in 
officinal  solution  of  potassa,  forming  clear,  deep  reddish-brown  solu- 
tions, the  color  probably  being  due  to  the  action  of  the  alkali  on  a 
peculiar  coloring  principle.  When  dilute  hydrochloric  acid  in  excess 
was  added  to  these  alkaline  solutions,  either  hot  or  cold,  dense  light- 
colored  precipitates  were  thrown  down.  In  this  respect  the  soft  resin 
of  jalap  differs  decidedly  from  the  resin  of  scammony,  with  which 
some  chemists  have  claimed  it  to  be  identical.  Resin  of  scammony  is 
wholly  soluble  in  ether  and  officinal  solution  of  potassa,  but  is  not  pre- 
cipitated from  its  alkaline  solution  upon  the  addition  of  dilute  hydro- 
chloric acid  in  excess. 
The  hard  resins — convolvulin  of  Mayer — were  also  weighed  and 
dissolved  in  officinal  solution  of  potassa.  When  dilute  hydrochloric 
acid  in  excess  was  added  to  these  solutions,  either  hot  or  cold,  no  pre- 
cipitate was  occasioned,  the  convolvulin  having  been  converted  by 
assumption  of  water  into  soluble  convolvulinic  acid. 
The  aqueous  solutions  from  the  extracts  were  evaporated,  and  the 
residues,  after  being  weighed,  were  exhausted  by  stronger  alcohol  to 
ascertain  the  amount  in  each  soluble  in  both  alcohol  and  water. 
In  examining  the  commercial  resins,  one  gram  of  each  was  dried, 
weighed,  exhausted  by  water  and  again  dried  and  weighed,  to  ascertain 
the  amount  of  moisture  and  extractive  matter  present.  One  gram  of 
each,  previously  exhausted  by  water  and  dried,  was  treated  with  stronger 
ether  to  separate  the  hard  and  soft  resins.  These,  after  being  weighed, 
were  treated  with  officinal  solution  of  potassa  and  dilute  hydrochloric 
