180 
Estimation  of  Alkaloids  in  Extracts. 
( Am.  Jour.  Pharm. 
\       April,  1887. 
cent  publications  by  Kunz  and  Schweissinger  and  also  Leuken,  who 
merely  gave  reactions  for  their  identity,  have  stimulated  a  desire  for 
further  research.  With  a  view  of  making  the  examination  of  narcotic 
extracts  also  a  subject  for  study  Dieterich  makes  a  critical  comparison 
and  gives  figures  after  trying  all  known  methods.  He  obtained  from 
extracts  of  belladonna,  aconite,  digitalis  and  hyoscyamus  all  the  reac- 
tions mentioned  by  Leuken ;  but  the  differences  in  color  between 
violet  and  raspberry  red  and  the  differences  between  heavier 
and  lighter  precipitation  and  color  (difference  between  bella- 
donna and  hyoscyamus)  are  not  so  great  as  to  allow  one  with  limited 
experience  to  come  to  any  positive  conclusions.  Schweissinger's  asser- 
tion that  unsophisticated  extract  of  belladonna  does  not  reduce  Feu- 
ling's  solution  has  not  been  confirmed  and  has  since  been  retracted  by 
•him. 
Schweissinger' s  method  for  determining  the  alkaloid  in  aconite,  bella- 
donna, hyoscyamus  and  nux  vomica  by  gravimetric  analysis  was  suc- 
cessful and  the  author's  figures  closely  correspond  with  those  given  by 
the  former  so  that  it  may  be  said  a  "  good  beginning  "  has  been  made. 
Instead  of  treating  the  extract  with  dilute  sulphuric  acid,  adding 
ammonia  and  shaking  with  chloroform,  Kunz  exhausted  with  alcohol, 
evaporated,  then  made  alkaline  and  treated  with  ether  and  lastly  with 
chloroform.  By  evaporating  the  ether  and  chloroform  solutions  the 
alkaloid  was  obtained  and  subjected  to  further  purification.  By  this 
method  he  undoubtedly  obtained  a  pure  alkaloid ;  but  it  must  be  taken 
into  consideration  that  he  operated  with  50  grams  of  extract.  Schweis- 
singer found  that  the  chloroform  would  not  emulsionize  so  readily 
with  the  alkaline  solution  of  the  extract,  and  went  a  step  further  in  not 
only  determining  the  alkaloid  gravimetrically  but  also  volumetrically. 
Dieterich  followed  Schweissinger's  method  and  the  alkaloid  obtained 
by  evaporating  the  chloroformic  solution  corresponded  in  weight  with 
that  found  by  Schweissinger,  but  did  not  correspond  with  the  figures 
obtained  by  titration  as  the  following  table  shows  : 
EXTEACT    OF  BELLADONNA. 
By  Weight  By  Titration. 
1.  1*060  per  cent,  alkaloid.  0  070  per  cent,  alkaloid. 
2.  1-020       "  "  0'116 
3.  1-320       "  «  0335 
4.  1-480       "  "  0-138 
5.  1-446       "  "  0-046 
6.  1-313       "  "  0-470  " 
