46  Assaying  of  A Ikaloidal  Drugs.       { Jg;  1Sfnn* 
rid  of  by  an  air-current  which  also  facilitates  the  final  drying.  The 
strychnine  is  generally  of  a  yellowish  color  due  to  traces  of  adhering 
coloring  matter;  it  must  always  be  tested  for  brucine  by  solution 
in  concentrated  sulphuric  acid  and  addition  of  a  small  crystal  of  potas- 
sium nitrate,  only  a  pale  yellow  color  being  allowable.  This  method 
is  also  satisfactory  in  testing  commercial  brucine  for  strychnine. 
Six  determinations  of  the  strychnine  in  the  alkaloids  from  nux 
vomica  gave  results  varying  from  45-1-50-6  per  cent.,  and  averag- 
ing 47-16  per  cent.,  confirming  the  statement  of  Beckurts  that  the 
two  alkaloids  are  present  in  about  equal  parts. 
Cinchona  bark  assays  are  made  by  a  very  much  simplified  Hau- 
bensack-Kuersteiner  method  (Am.  Journ.  Pharm.,  189T,  347;  1893^ 
71).  12  gm.  of  the  dried  and  finely  powdered  bark  are  placed  in  a  vial 
of  250  gm.  capacity,  120  gm.  ether  and  after  agitation  10  cc.  ammo- 
nia (10  per  cent.)  added  and  the  mixture  repeatedly  shaken  during 
half  an  hour  ;  if  the  bark  to  be  assayed  is  succirubra  10  cc,  if  calisaya, 
15  cc.  water  are  added  and  the  mixture  agitated  for  one  minute; 
IOO  gm.  of  the  ethereal  solution  (which  from  succirubra  is  perfectly 
clear,  from  calisaya,  however,  is  somewhat  turbid)  briskly  agitated 
in  a  flask  with  3  cc.  dilute  sulphuric  acid  and  37  cc.  water  and 
allowed  to  stand  for  about  ten  minutes  when  a  perfect  separation 
will  allow  of  the  decanting  of  the  greater  portion  of  the  ethereal 
layer,  the  remainder  is  transferred  along  with  the  acid  solution  to  a 
small  separator  and  the  acid  solution  allowed,  to  run  off  into  a 
beaker  and  the  flask  and  separator  rinsed  with  10  cc.  water;  the 
acid  solution  is  freed  from  ether  by  warming  and  replaced  in  the 
cleansed  separator,  where  it  is  agitated  with  a  mixture  of  30  gm. 
chloroform  and  10  gm.  ether  along  with  5  cc.  ammonia  water. 
The  chloroform-ether  solution  is  run  into  a  flask  and  the  agitation 
repeated  with  15  gm.  chloroform  and  5  gm.  ether;  the  united  alka- 
loidal  solutions  are  filtered  through  a  small  chloroform-wetted  filter 
into  a  tared  flask  and  the  solvents  distilled  off.  The  alkaloids  from 
calisaya  are  generally  crystalline,  from  succirubra  amorphous  and 
retaining  chloroform  ;  by  the  addition  of  3  to  5  cc.  absolute  alcohol 
and  boiling  this  away  in  a  water-bath  the  alkaloids  are  obtained 
crystalline  and  capable  of  being  easily  dried  at  ioo°  C;  a  higher 
temperature  is  to  be  avoided.  The  weighed  alkaloids  may  be 
titrated  by  dissolving  in  10  to  15  gm.  alcohol,  adding  water  until 
precipitation  commences,  and  titrating  with        hydrochloric  acid 
