Am.  Jour.Pharm. 
Feb.,  1893. 
Alkaloidal  Assaying. 
79 
apparatus  ;  (2)  the  difficulty  in  obtaining  complete  extraction  ;  (3) 
a  number  of  the  alkaloids  are  easily  decomposed  by  the  calcium 
hydrate,  especially  brucine,  hyoscyamine,  atropine,  etc.;  (4)  The 
very  great  difficulty  in  preventing  the  ether  from  carrying  particles 
of  the  calcium  hydrate  into  the  ethereal  solution;  some  of  these 
difficulties  cause  a  loss  of  alkaloids,  the  last-mentioned  an  increase 
in  the  yield  of  alkaloid.  Dr.  A.  Partheil's  modification  of  this 
method  (Am.  Journ.  Pharm.,  1892,  521)  is  rather  a  complication  of 
the  method  without  correcting  any  of  its  fallacies.  (II)  Beckurts'  and 
Hoist's  method  (a  modification  of  Dragendorff's  method  in  which 
the  objectionable  emulsifying  is  prevented  by  extracting  dilute  alco- 
holic extract  solution  with  three  portions  of  chloroform  of  20,  10 
and  10  cc,  respectively,  distilling  off  the  chloroform  from  the  mixed 
chloroform  solutions,  dissolving  the  residue  in  warm  yL-  ^-hydro- 
chloric acid,  filtering,  washing  the  filter  with  water  and  titrating 
the  solution  with  yj-g-  /z-alkali,  using  cochineal  as  indicator)  which 
generally  gives  agreeing  results,  possesses  also  some  disadvantages, 
(1)  Although  the  addition  of  alcohol  at  first  prevents  the  emulsify- 
ing, the  solubility  of  alcohol  in  chloroform  and  hence  its  removal 
causes,  especially  in  the  third  extraction,  considerable  trouble  in 
separating  the  chloroform ;  (2)  owing  to  the  presence  of  the  alcohol 
the  alkaloid  obtained  is  rather  impure  and  colored ;  (3)  numerous 
experiments  show  that  the  three  portions  of  chloroform  will  not 
completely  remove  the  alkaloid ;  to  effect  this  the  liquid  must  be 
extracted  with  chloroform  until  no  precipitation  occurs  upon  acidi- 
fying and  adding  Mayer's  reagent ;  (4)  it  requires  too  much  time, 
(III)  Schweissinger  and  Sarnow's  method  (Am.  Journ.  Pharm. , 
1 89 1,  96)  (in  which  a  concentrated  aqueous  solution  of  the  extract 
made  alkaline  with  ammonia  is  agitated  with  a  relatively  large 
quantity  of  a  mixture  of  chloroform  and  ether  and  then  a  portion 
only  of  the  alkaloidal  solution  evaporated  and  weighed  or  titrated 
with  ^-acid  using  cochineal  as  indicator ;  the  solvent  can  be  a 
mixture  of  chloroform  and  ether,  which  may  be  lighter  or  heavier 
than  water  as  may  seem  desirable)  after  numerous  series  of  experi- 
ments is  hailed  as  the  method  containing  the  basis  upon  which 
future  Pharmacopoeias  will  form  their  alkaloidal  assays ;  as  advan- 
tages are  stated  :  (1)  That  no  special  apparatus  fs  required ;  (2)  by 
the  use  of  the  mixed  solvent  no  emulsion  is  formed  ;  (3)  the 
rapidity  of  its  execution  ;  (4)  with  proper  modification  it  is  suitable 
