340 
TESTS  FOR  THE  CINCHONA-ALKALOIDS. 
of  a  considerable  number  of  barks  which  were  hitherto  unknown  ; 
as  for  example,  the  barks  containing  quinidine  and  paricine,  and 
the  numerous  sorts  of  the  so-called  yellow  barks;  and  it  may  with- 
out hesitation  be  asserted  that  these' barks  contain  also  a  larger 
number  of  alkaloids  than  is  known  at  present. 
I  have  read  with  much  interest  WeddelPs  excellent  work,  from 
which  Dr.  Riegel  some  time  since  extracted  (see  Pharmaceutical 
Journal,  vol.  ix.,  p.  224)  the  information  which  is  of  most  impor- 
tance to  the  Pharmaceutist.  Although  I  am  far  from  undervaluing 
the  high  merits  of  this  distinguished  traveller,  the  successor  of 
Humboldt  and  Poppig,  I  am,  notwithstanding,  of  opinion  that  too 
great  importance  must  not  be  attached  to  his  researches.  I  con- 
sider that  his  proposal  to  determine  the  goodness  of  barks  by  their 
anatomical  structure,  has  no  greater  value  than  as  an  application 
to  botany  generally,  and  to  vegetable  physiology  in  particular,  for  I 
have  convinced  myself  by  numerous  and  most  carefully  performed 
experiments,  that  his  assertion,  that  the  shortly  fibrous  barks  con- 
tain the  largest  proportion  of  alkaloid  cannot  be  admitted,  as  its 
truth  has  been  directly  disproved.  It  is  only  applicable  to  calisaya 
bark,  and  even  in  that  case  has  many  exceptions.  Were  this  alone 
sufficient  to  raise  doubts  about  the  possibility  of  judging  of  the 
goodness  of  barks  by  their  structure,  there  is  also  another  circum- 
stance to  be  taken  into  consideration.  The  anatomical  structure  of 
bark  is,  as  is  well  known,  uninterruptedly  progressiveduring  vege- 
tation :  each  stage  offers  a  new  formation,  the  bark  of  the  trunk 
appears  very  different  from  that  of  the  larger  branches,  and  that  of 
these  varies  again  in  its  structure  from  the  bark  of  the  smaller 
branches.  Lastly,  we  ought  to  examine  the  barks  as  Weddell  did, 
in  their  fresh  condition,  in  order  to  be  enabled  to  judge  of  their 
structure.  These  views  of  Weddell's,  however  interesting  they 
may  be  in  other  respects,  are,  I  am  convinced  of  a  very  subordinate 
value  for  medical  practice.  We  must,  therefore,  still  follow  the 
chemico-analytical  route,  if  we  wish  to  establish  a  scientific  and 
safe  classification  of  the  cinchona  barks. 
Dr.  Riegel  was  no  doubt  of  the  same  opinion,  when  he  appended 
to  his  extract  from  Weddell's  work  a  synopsis  of  all  the  known 
methods  of  determining  the  proportion  of  alkaloids ;  and  I  am  much 
surprised  how  he,  under  these  circumstances,  could  express  some 
doubts  whether  my  experiments  perfectly  agreed  with  Weddell's 
