Am.  Jour.  Pharm.  \ 
February,  1896.  J 
The  Assay  of  Cinchona  Bark. 
79 
The  bark  and  wood  showed  also  a  distribution  of  tannin  similar  to 
that  described  in  the  other  species,  and  the  precipitate  which  it 
.  produced  with  ferric  chloride  solution  was  greenish  black.  It  should 
be  observed  that  in  this  species,  in  P.  rigida  and  in  P.  Austriaca,  the 
tannic  precipitate  had  in  a  few  of  the  cells  a  bluish  black  appear- 
ance under  the  microscope,  probably  owing  to  the  presence  in 
these  cells  of  other  bodies  related  to  tannin,  which  were  precipitated 
by  the  same  reagent. 
A  COMPARISON  OF  THE  MORE  RECENT  METHODS^ 
FOR  THE  ASSAY  OF  CINCHONA  BARK. 
BY  IyYMAN  F.  Kebi^R. 
No  less  an  authority  than  Dr.  Fr.  Hoffmann,  in  a  review  of  a  recent 
text-book  of  pharmacy,  commented  on  its  omissions  as  follows  : 
"Among  the  latter  (omissions)  may  be  mentioned  the  desirable  intro- 
duction of  a  chapter  on  the  valuation  or  estimation  of  alkaloidal 
galenical  preparations,  a  subject  of  constantly  increasing  importance 
in  manufacturing  and  dispensing  pharmacy.  Although  still  in  a 
state  of  evolution  and  imperfection,  several  methods  of  considerable 
value  for  the  identification  and  estimation  of  drugs,  as  well  as  their 
fluid  extracts  and  tinctures,  have  been  established  during  recent 
years.  The  importance  of  the  application  of  pharmaceutical  re- 
search in  this  direction,  and  the  valuation  of  the  therapeutical  con- 
stants of  important  plant  remedies,  is  now  of  such  a  recognized 
prominence  that  it  is  one  of  the  foremost  problems  in  pharmacy." 
In  selecting  a  method  for  assaying  cinchona  bark,  due  considera- 
tion must  be  given  to  the  kind  of  information  desired.  While  the 
pharmacist  does  not  require  as  elaborate  a  method  for  standardizing 
his  preparations  as  the  manufacturer  of  quinine  in  selecting  his 
barks,  yet  he  ought  to  be  in  possession  of  a  process  that  yields  no 
less  accurate  and  satisfactory  results  in  a  comparatively  short  time. 
The  methods  considered  most  efficient  and  practicable  for  extract- 
ing the  alkaloids  both  from  the  bark  and  its  galenical  preparations 
may  be  classed  as  follows : 
(i)  The  powdered  bark  or  its  preparations  are  macerated  with 
ether  and  ammonia  water,  or  a  mixture  of  chloroform,  ether  and 
